Optical device substrate film-formation apparatus, optical disk substrate film-formation method, substrate holder manufacture method, substrate holder, optical disk and a phase-change recording type of optical disk

ABSTRACT

In an optical disk substrate film-formation apparatus which prepared an optical disk by forming a thin film on a substrate, the optical disk substrate is held by a holder section. A contact support surface is provided to the holder section which closely contacts at least a portion of the surface of the optical disk substrate rear to the surface where the think film is formed.

FIELD OF THE INVENTION

The present invention relates to an optical disk manufacture technology.More specifically this invention relates to an optical disk substratefilm-formation apparatus used for forming a film such as a recordinglayer by means of sputtering on a surface of an optical disk substrate,a film-formation method using the optical disk substrate film-formationapparatus, a method of manufacturing a substrate holder constituting theapparatus, a substrate holder constituting the apparatus, an opticaldisk manufactured with the apparatus, and a phase-change recording typeof optical disk in which an Ag-based alloy is used for thereflection/heat-emission layer. This technology is applicable in theoptical medium (such as a CD-ROM, a CD-R, a CD-RW, a DVD, a DVD-R, aDVD-RW, a DVD+RW, a DVD-RAM or the like).

BACKGROUND OF THE INVENTION

In the conventional technology, an optical disk is generallymanufactured by alternately laminating a dielectric body layer and arecording layer on a substrate (optical disk substrate) made from such amaterial as thermoplastic resin. In most cases, the optical disk asdescribed above is manufactured with a film-formation apparatus based onthe so-called sheet system which can form a film on a plurality ofoptical disk substrates respectively in batch.

Some of film-formation apparatus based on the sheet system and used formanufacturing optical disk substrates have a plurality of film-formationchambers in each of which film-formation is performed. In that case thefilm-formation chambers are linked to each other with one substratecarriage chamber. In the film-formation apparatus as described above,optical disk substrates once carried into the apparatus are successivelycarried through the substrate carriage chamber to each film-formationchamber, where a different type of dielectric body layer or a recordinglayer is formed and laminated, and then the substrate each with a filmformed thereon are taken out to outside of the apparatus. With thefilm-formation apparatus as described above, a plurality of dielectricbody layers or recording layers can be formed, which contributes tothrough-put in a film-formation step.

The film-formation chamber and substrate carriage chamber each in afilm-formation apparatus are separated from each other with a substrateholder for holding an optical disk substrate on which a film is beingformed. FIG. 42 shows a cross section of the substrate holder asdescribed above.

The substrate holder 100 shown in FIG. 42 has a round support plate 35on which an optical disk substrate 101 is placed, and an arm section 37for holding the support plate 35. Provided on the support plate 35 arean inner mask 38 which fixes an optical disk substrate 101 at a positionclose to its center (described as fixing section A) and an outer mask 39which fixes the optical disk substrate 101 at a position close to itsperipheral section (described as fixing section B). As shown in thisfigure, the optical disk substrate 101 is held and fixed between theinner mask 38 and outer mask 39.

The substrate holder 100 fixes the optical disk substrate 101 in such away that the fixing section A and fixing section B contact the supportplate 35 and there is a clearance a between other portion and thesupport plate 35. Thus, the optical disk substrate 101 can easily beremoved from the support plate 35, which prevents the optical disk frombeing broken when removed from the support plate 35.

In recent years, there is the strong need for enlarging a recordingcapacity of an optical disk from 650 MB to 4.7 GB. To satisfy this need,there is the technology of adhering two optical disks to each other sothat data can be recorded on both sides of the optical disk. In thistype of optical disk based on the adhesion system, it is necessary toreduce the thickness of the optical disk from 1.2 mm like in theconventional technology to 0.6 mm. When the optical disk substrate isthin, naturally the mechanical and thermal strength decreases. When thethermal strength lower, the optical disk gets deformed during the filmformation, and number of conceivably defective products which do notsatisfy the requirements increases. This problem is especially seriouswhen it is tried to maintain a through-put in the film formation step asthat in the conventional technology.

In an optical disk (optical recording disk), a data recording sectionwhich can optically record and reproduce data is provided on asubstrate, and the optical disk is used as a disk for filing documentsor data therein. When the optical disk is used, the disk is rotated at ahigh speed, and a laser beam focused to a diameter of around 1 μm isirradiated thereon, and data is read out from the recording layer ordata is recorded in the recording layer executing focus adjustment andpositional detection.

When manufacturing various types of optical disk media, a step offorming a reflection layer, a recording layer, a dielectric body layer,or a protection layer by sputtering is indispensable. In film formationby sputtering, Ar plasma or the like is generated in a vacuum, a surfaceof a target is hit by ions in this plasma, and a film is piled up on anopposite substrate, so that heat is inevitably generated during filmformation by sputtering. In the optical disk, generally a polymericmaterial such as polycarbonate is used as a material for a disksubstrate, so that temperature increase in the film-formation chambermay sometimes cause deformation of the disk substrate. This problembecomes especially serious when film formation is continuously executedat a high speed, when a thick film is formed, or when two or more layersare repeatedly formed on the same substrate, and is still further serieswhen the method is applied to manufacture a thin substrate with athickness of 0.6 mm used in the DVD media.

To solve the problem described above, for instance, Japanese PatentLaid-Open Publication No. HEI 10-81964 (Title of the Invention: SputterHolder for an Optical Recording Medium and Optical Recording MediumManufacture Method) proposes a sputter device for manufacturing anoptical recording medium, in which a sputter holder (substrate holder)for holding a substrate on which a film is to be formed having differentheights in the outer section and inner sections each contacting asubstrate is provided, a substrate is placed on this substrate holder,and deformation of the substrate is reduced by executing sputterfilm-formation in a state where the substrate is bent in a directionreverse to that in which the substrate is bent during film-formation bysputtering.

Further in the conventional technology, when a plane substrate is loadedon a substrate holder of a vacuum film-formation apparatus (an opticaldisk substrate film-formation apparatus) for film formation tomanufacture an optical disk, gas in a clearance between a rear surfaceof the substrate and the substrate holder is hardly evaluated to avacuum state, and a time required to evaluate the gas down to aprespecified pressure level may be disadvantageously long. In addition,when a substrate with a film having been formed is carried out from thefilm-formation apparatus, sometimes the substrate is kept in a statewhere the substrate is vacuum-adsorbed to the substrate holder and ishardly separated from the substrate holder, which causes troubles inoperations for taking out and carrying the substrate.

To solve the problem described above, for instance, Japanese PatentLaid-Open Publication No. HEI 2-273345 discloses a holder based on astructure in which an evacuation hole is provided in a recording mediumsubstrate holder. Further, Japanese Utility Model Laid-Open PublicationNo. HEI 4-137526 discloses a holder based on a structure in which a gasevacuation hole is provided in a recording medium substrate holder aswell as a substrate holder (opposite to a recording surface). In theseconventional technologies, it is tried to evacuate gas on a rear surfaceof a substrate and to prevent adsorption of a substrate by providing agas evacuation hole in a substrate holder.

In recent years, an optical disk making use of phase-change is oftenused as a rewritable optical disk. Generally the phase-change recordingtype of optical disk comprises a transparent plastic substrate on whichconvex and concave sections are provided at an arbitrary pitch, a lowerdielectric body protection layer using ZnS—SiO₂ as a dielectricmaterial, a phase-change recording layer using a chalcogen-basedrecording material such as GeSbTe, InSbTe, or AgInSbTe, an upperdielectric body protection layer made from ZnS—SiO₂ like in the lowerdielectric body protection layer, and a reflection/heat-emission layerusing mainly an Al-based alloy, Au, or Ag, and each of the layers isalso formed by sputtering.

In Japanese Patent Laid-Open Publication No. HEI 10-8964, however,warping in a radial direction of a substrate is taken intoconsiderations, but there is no countermeasures against the mechanicalcharacteristics of the substrate in a peripheral direction of thesubstrate, and when viewed totally, countermeasures against deformationof a substrate which occurs during film formation by sputtering is notalways appropriate.

For instance, in production of DVD media, generally a film is formed bysputtering on a substrate having a thickness of 0.6 mm, and then a blanksubstrate having a thickness of 0.6 mm is adhered to the formersubstrate. As it is difficult to correct warping of a substrate in theperipheral direction in the adhesion step, it is essential to suppresswarping of a substrate in the peripheral direction during film formationby sputtering, but this objective has not successfully been achieved inthe conventional technology.

With the inventions disclosed in Japanese Patent Laid-Open PublicationNo. HEI 2-273345 or in Japanese Utility Model Laid-Open Publication No.HEI 4-137526, although it is possible to prevent vacuum adsorption whentaking out a substrate from a substrate holder, in a case of substratemade from a plastic material, when incident energy from particlessputtered during film formation is accumulated, temperature of thesubstrate easily rises due to accumulation of heat in the substrate madefrom the plastic material, and if a groove for preventing vacuumadsorption is formed on a surface of a holder closely contacting a rearsurface of a substrate, difference between temperature in the closelycontacting section and that in the groove section is generated, and anew problem of thermal deformation of a substrate occurs.

As described above, in the case of a substrate made from a plasticmaterial, sometimes incident thermal energy may negatively affect themechanical precision of the substrate. Especially when fine bits likethose in an optical disk are formed on a surface, lowering of themechanical precision due to deformation causes big troubles inrecording, reading, or deleting data. Further, in production of varioustypes of optical disk, a step of forming a reflection layer, a recordinglayer, a dielectric body layer, and a protection layer with a sputterdevice continuously and successively at a high speed is indispensable,so that the introduced thermal energy is easily accumulated. Especially,when a thin substrate having a thickness of 0.6 mm like a DVD mediasubstrate is used, thermal deformation easily occurs, so that thisproblem is extremely serious in relation to maintenance of themechanical precision.

When a trouble occurs due to thermal deformation of a substrate or forsome other reasons while the substrate is being carried, it not onlycauses a failure of the device, but also extremely lowers theproductivity of the production facility, which may in turn causes costincrease, and lowering of productivity or the like. Further, when thevacuum adsorption occurs in a step of taking out a substrate from asubstrate holder, even if the substrate can be separated from thesubstrate holder in the carriage system side, scratches or other damagesmay be generated on a rear surface of the substrate, which in turnslowers the production yield, and further it may cause a serious problemin realization of a substrate carriage process at a higher speed.

In the case of phase-change recording type of optical disk, when it istried to raise power for sputtering in film formation, temperature ofthe substrate remarkably rises, which causes warping of the substratewith reproduction of recorded data disabled. A recording disk based on aDVD system with a small thickness is especially weak to heat.

Japanese Patent Laid-Open Publication No. HEI 10-162435 discloses aninvention relating to a reflection layer in a phase-change recordingtype of optical disk, and in this invention a mixture of Mg and Ag orthe like is used for the reflection layer to improve the repetitionperformance.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an optical disksubstrate film-formation apparatus and an optical disk substratefilm-formation method which do not deform the optical disk substrateeven when the optical disk with a thickness of 0.6 mm or less is used,nor lowers the through-put.

It is another object of the present invention to make it possible totake out and carry a substrate with a film having been formed bysputtering efficiently at a high speed in an apparatus used for forminga film by closely contacting at least one portion of a rear surface of asection of an optical disk substrate in which a thin film is formedduring film formation by sputtering to a substrate holder.

It is still another object of the present invention to reducedeformation of a substrate during film formation by sputtering andrealize stable carriage of the substrate.

It is still another object of the present invention to provide anoptical disk substrate film-formation apparatus which can suppressdeformation of a substrate and prevent vacuum adsorption between asubstrate and a substrate holder when taking out the substrate from thesubstrate holder after a film has been formed by sputtering and thus canexecute an stable operation for taking out substrates and also toprovide a substrate holder used in the optical disk substratefilm-formation apparatus described above.

It is still another object of the present invention to realize stableand high yield production of optical disks insuring the excellentmechanical characteristics of the substrate and media signalcharacteristics and to reduce troubles and further realize the highserviceability even when forming a film on a thick disk or on a thindisk at a high speed or when repetitively forming two or more layers onthe same substrate in an optical disk substrate film-formationapparatus.

It is still another object of the present invention to reducedeformation of a substrate generated during film formation by sputteringand realize stable carriage of a substrate, and further to preventgeneration of scratches on a surface of a substrate due to close contactbetween a substrate and a substrate holder.

It is still another object of the present invention to provide aphase-change recording type of optical disk in which the substrate iswarped little even when a phase-change recording film is formed bysputtering at a high speed on such optical recording media as a CD-RW orDVD-RW, and also in which degradation of the Ag-basedreflection/heat-emission layer is suppressed.

With the configuration according to the present invention, an area inwhich a substrate is held by a substrate holder increases, and loss ofsubstrates during film formation due to thermal or plastic deformationis reduced. Further a rear surface of a film-formed area of a substratecan be adsorbed with vacuum chuck to a substrate holder.

With the configuration of the present invention, an area in which asubstrate is held by a substrate holder increases, and also in a case ofsubstrates with a thickness of 0.6 mm or less, loss of substrates duringformation due to thermal or plastic deformation is reduced. Further, arear surface of a film-formed area of a substrate can be adsorbed withvacuum chuck to a substrate holder.

With the configuration according to the present invention, it ispossible to present a light beam incidence surface of an optical diskwhich is in the rear side during film formation from being damaged.

With the configuration according to the present invention, a portion ofa contact holding surface of a substrate holder does not closely contacta substrate, so that an adhesion force between the contact holdingsurface and the substrate can be adjusted.

With the configuration according to the present invention, a substratesucked to the contact holding surface with vacuum chuck can easily beremoved.

With the configuration according to the present invention, it ispossible to adsorb a substrate and a substrate holder to each otherbecause of a pressure difference between a film formation chamber and asubstrate carriage chamber, so that any specific mechanism for adsorbingthe substrate and substrate holder to each other is not required.

With the present invention, by making rough a substrate holding surfaceof a substrate holder, it is possible to suppress warping of a substratein the radial and peripheral directions, and a substrate does notclosely contact a substrate holder, so that the efficiency in separatinga substrate from a substrate holder is improved.

With the present invention, by making the surface roughness Rmax of atleast a portion of a substrate holding surface to 10 μm or more and 500μm or less, the efficiency in separating a substrate from a substrateholder is further improved. In this case, it is preferable to makingrough the entire substrate holding surface within the numerical valuerange. When the surface roughness Rmax of the holding surface is lessthan 10 μm, the efficiency in separating a substrate from a substrateholder is not adequate, and when the roughness Rmax exceeds 500 μm, thesubstrate easily deforms along the rough surface.

With the present invention, to manufacture a substrate holder, a degreeof the surface roughness of a substrate holding surface is shifted to ahigher value than that in the range described above, and then thesurface roughness Rmax is adjusted to the range described above afterthe prespecified lubrication processing is executed (the surfaceroughness is lowered after execution of the processing). To lubricatethe rough surface, generation of damages on a rear surface of asubstrate due to transfer of the substrate holding surface can beprevented. In the present invention, the lubrication processing may becarried out to both the roughed portion and plane surface portion of theholding surface, or only to the plane surface section.

With a substrate holder according to the present invention, generationof damages on a rear surface of a substrate can be suppressed. Such amaterial as PTFE (polytetrafluoroethylene) or POM (polyacetal) may beused as the self-lubricating plastic material. In the present invention,an area made from the self-lubricating plastic material may be theroughed portion and other sections of the substrate holding surface, oronly sections other than the roughed portion.

With the functions according to the present invention, even when filmformation is carried out closely contacting a rear surface of asubstrate on which a film is to be formed to a substrate holder, bysupplying gas from a gas supply section when the substrate is taken outafter film formation by sputtering, it is possible to remove a substratevacuum-adsorbed to a substrate holder via a step of film formation bysputtering in a vacuum. Further as the vacuum release phenomenon by gasis utilized, damages to a rear surface of a substrate when a substrateis taken out can be eliminated.

With the configuration according to the present invention, an area inwhich a substrate is held by a substrate holder increases, and loss ofsubstrates during film formation due to thermal or plastic deformationis reduced. Further, it is possible to adsorb a rear surface of afilm-formed area of a substrate to a substrate holder with vacuum chuck.

With the configuration according to the present invention, an area inwhich a substrate is held by a substrate holder increases, and loss ofsubstrates during film formation due to thermal or plastic deformationis reduced even in the case of a substrate with a thickness of 0.6 mm orless. Further, it becomes possible to adsorb a rear surface of afilm-formed area of a substrate to a substrate holder with vacuum chuck.

With the configuration according to the present invention, a substratecan be adsorbed to a substrate holder during film formation withoutproviding any special mechanism for adsorbing a substrate to a substrateholder.

With the configuration according to the present invention, it ispossible to adsorb a substrate to a substrate holder during filmformation without providing any special mechanism for adsorbing asubstrate to a substrate holder even in the case of substrate with thethickness of 0.6 mm or less.

With the configuration according to the present invention, an area inwhich a substrate is held by a substrate holder during film formationincreases, and deformation of a substrate due to heat during filmformation is reduced.

With the configuration according to the present invention, generation ofdamages on a light beam incidence surface of an optical disk which is inthe rear side during film formation can be prevented.

With the configuration according to the present invention, a protectionfilm can be formed without heating a substrate.

With the configuration according to the present invention, a protectionfilm can be formed even when such a device as a coater is not available.

With the configuration according to the present invention, a film madefrom a material suited to a protection with the conditions for filmformation well known can be selected.

With the film-formation method according to the present invention,warping of a substrate in the radial and peripheral directions thereofcan be suppressed, and in addition, the substrate can easily andsmoothly be separated from a substrate holder.

With complex plating according to the present invention, a coating filmmade from a carbon fluoride (CF)n or fluororesin is formed on a roughedportion on a surface of a substrate. As the fluororesin, for instance,PTFE, PFA (tetrafluoroethylene-perfluoroalkylvinyl ether copolymer), andFEP (tetrafluoroethylene-hexafluoropropylene copolymer) can be used.

With the organic plating according to the present invention, an organicthin film made from triazinthiole is formed a roughed portion on asurface of a substrate.

Other objects and features of this invention will become apparent fromthe following description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top surf ace of a substrate carriage chamber as well asof a film format ion chamber common to first to third embodiments of thepresent invention;

FIG. 2 shows a sideward cross-section according to the first embodimentof the present invention;

FIG. 3 is a view showing configuration of a holder section according tothe first embodiment, and shows a top section of the holder section(lower) and a cross section (lower) taken along the dashed line A-A′shown in the upper view;

FIG. 4 shows a state in which a silicon rubber section is provided in acontact holding surface S′ of the holder section according to the firstembodiment;

FIG. 5 shows configuration in which a claw is provided in the holdersection shown in FIG. 2;

FIG. 6 shows a top section of a holder according to the secondembodiment (upper), and a cross section (lower section) taken along theline A-A′ shown in the lower view;

FIG. 7 shows a top section of a holder section (lower) according to thethird embodiment, and a cross section (upper) taken along the dashedline A—A in the lower view;

FIG. 8 shows effects due to the first to third embodiments of thepresent invention;

FIG. 9 is a view showing contents shown in FIG. 8 in a form of graph;

FIG. 10 is a cross-sectional view showing a substrate holder accordingto a fourth embodiment of the present invention, and shows a state inwhich the substrate holder is holding a substrate;

FIG. 11 is a flat view showing the substrate holder shown in FIG. 10,and shows a state before a substrate is held thereon;

FIG. 12 is a cross-sectional view showing a substrate holder based onthe conventional technology, and shows a state where a substrate isloaded thereon;

FIG. 13 is a general flat view showing a key section in a seventhembodiment of the present invention;

FIG. 14 is a general cross-sectional view showing the substrate holderaccording to the seventh embodiment and an optical recording mediumsubstrate loaded on the substrate holder;

FIG. 15 shows an example of a form of a porous member used in thesubstrate holder according to the present invention;

FIG. 16 is a general flat view showing a key section in an eighthembodiment of the present invention;

FIG. 17 is a general partial cross-sectional view showing a substrateholder according to the eighth embodiment of the present invention, anda optical recording medium substrate loaded on the substrate holder;

FIG. 18 is a general block diagram showing a key section of an opticaldisk substrate film-formation apparatus according to a ninth embodimentof the present invention;

FIG. 19 is a general block diagram showing a key section of an examplefor comparing a difference in the film-formation performance from thatin the optical disk substrate film-formation apparatus according to theninth embodiment due to a different in construction thereof;

FIG. 20 is a general block diagram showing a key section of anotherexample for comparing a difference in the film-formation performancefrom that in the optical disk substrate film-formation apparatusaccording to the ninth embodiment due to a different in constructionthereof;

FIG. 21 is a table showing configuration of a substrate sample used forassessing a warping amount of a substrate and stability of the substrateduring transportation;

FIG. 22 is a table showing types of substrate holder and a raping rateof a substrate;

FIG. 23 is a table showing a result of assessment of a warping amount ofa substrate and stability in loading onto or unloading each substratefrom a substrate holder changing a contact area between a substrateholder and a substrate in an optical disk substrate film-formationapparatus according to a tenth embodiment of the present invention;

FIG. 24 is a table showing a result of assessment of a warping amount ofa substrate and damages generated on a surface of a substrate executedby changing a taper angle of an edge section in a substrate holdingsection of a substrate holder;

FIG. 25 is a partial view showing a form of taper at an edge section ina substrate holding section of a substrate holder according to aneleventh embodiment of the present invention;

FIG. 26 is a table showing a result of assessment of a warping amount ofa substrate and stability thereof during transportation executed bychanging a width of a silicon rubber provided in an edge section of asubstrate holder;

FIG. 27 is a block diagram showing a portion of the silicon rubberprovided in an edge section of a substrate holder according to a twelfthembodiment of the present invention;

FIG. 28 is a general cross-sectional view showing an optical disksubstrate film-formation apparatus;

FIG. 29 shows an example of a substrate holder section used in anoptical disk substrate film-formation apparatus according to athirteenth embodiment of the present invention;

FIG. 30 is an enlarged view showing a gas supply path section in theframe shown in FIG. 29;

FIG. 31 is an enlarged view showing another gas supply path section inthe frame shown in FIG. 29;

FIG. 32 shows configuration of a substrate holder section used in anoptical disk substrate film-formation apparatus according to afourteenth embodiment of the present invention;

FIG. 33 shows configuration of a substrate holder used in an opticaldisk substrate film-formation apparatus according to a fifteenthembodiment of the present invention;

FIG. 34 is a general top view showing a sheet type of optical disksubstrate film-formation apparatus for forming a multi-layered film;

FIG. 35 shows a cross section of a substrate holder based on theconventional technology;

FIG. 36 shows an example of a substrate holder used in the apparatusaccording to the present invention;

FIG. 37 shows another example of substrate holder used in the apparatusaccording to the present invention;

FIG. 38 shows another example of a substrate holder based on theconventional technology;

FIG. 39 shows a result of measurement of mechanical characteristics of asubstrate;

FIG. 40 shows a result of measurement of media signal characteristics;

FIG. 41 is a general block diagram showing an example of a phase-changerecording type of optical disk according to a seventeenth embodiment ofthe present invention; and

FIG. 42 shows an example of a cross section of a substrate holder basedon the conventional technology.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The optical disk substrate film-formation apparatus, optical disksubstrate film-formation method, substrate holder manufacture method,and a phase-change recording types of optical disk according to first toseventeenth embodiments of the present invention are described in detailbelow with reference to the related drawings.

FIG. 1 shows top views of a substrate carriage chamber and afilm-formation chamber of an optical disk substrate film-formationapparatus according to the first embodiment of the present invention,and the basic configuration as described below is common to the first tothird embodiments. In any of the first to third embodiments, it isassumed that the optical disk substrate with the thickness of 0.6 mm isused. The thickness of the substrate includes a nominal allowance of ±50μm.

The configuration shown in the figure comprises a substrate carrierchamber 10, film-formation chambers 2 a to 2 e provided on an externalperipheral surface of the substrate carriage chamber 10, and substrateholders 6 a to 6 f for fixing optical disks 1 (Refer to FIG. 2) in thefilm-formation chambers 2 a to 2 e. Vacuum is maintained in thesubstrate carriage chamber 10, and an optical disk substrate 1 iscarried to each film-formation chamber without breaking the vacuumstate. A carry-out/carry-in port 20 has a load lock mechanism betweenthe vacuumed compartment and the atmospheric pressure, and has afunction to load or unload the optical disk substrate 1 to and from asubstrate holder f. The substrate holders 6 a to 6 f are describedhereinafter.

Substrate carriage arms 4 a to 4 f are connected to the substrateholders 6 a to 6 f, and the substrate carriage arms 4 a to 4 f are fixedon a central section 30. The central section 30 is rotated by a drivingsection not shown herein. In association with this rotation, thesubstrate holders 6 a to 6 f can successively set one optical disksubstrate in the film-formation chambers 2 a to 2 e.

In the first embodiment, the optical disk substrate film-formationapparatus having the configuration as described above forms three typesof films made from AgInSbTe, ZnS.SiO₂, and Al by means of sputtering.Because of this feature, in the first embodiment, the film-formationchambers 2 a and film-formation chambers 2 b are used dedicatedly forformation of a ZnS.SiO₂ film (dielectric body layer), the film-formationchamber 2 c is used dedicatedly for formation of an AgInSbTe film(storage layer), the film-formation chamber 2 d is used dedicatedly forformation of an ZnS.SiO₂ film (upper dielectric body layer), and furtherthe film-formation chamber 2 e is used dedicatedly for formation of anAl film (reflection layer). By successively setting one optical disk 1in the film-formation chambers 2 a to 2 e, the films described above areformed continuously, thus the optical disk being formed.

In any of the first to third embodiments, the total film thickness offilms formed as described above is 370 nm. A tact time in the sputteringstep is 25 sec.

FIG. 2 is a lateral cross section of the substrate holder 6 a shown inFIG. 1. The other substrate holders 6 b to 6 f are formed in the sameway as the substrate holder shown in FIG. 2, so that description andillustration thereof are omitted herein. The substrate holder 6 a has aholder section 3 which is a disk for fixing the optical disk 1, and anarm section 4 a for supporting a holder section 3 at its center. Thisholder section 3 fixed the optical disk substrate 1 to thefilm-formation chamber 2 a.

The optical disk substrate 1 is fixed by an inner mask 11 and an outermask 12 to the holder section 3, and a film is formed only in an area Sof the optical disk substrate exposing from the inner mask 11 as well asfrom the outer mask 12 (film-formed area).

In the first embodiment, a through-hole 7 a (indicated by a dash and dotline) for vacuum chuck is provided in the arm section 4 a, and vacuumchuck section is provided in the holder section 3. With the vacuum chucksection as described above, the optical disk substrate 1 is more tightlyfixed to the holder section 3.

FIG. 3 shows a basic configuration of the holder section 3 describedabove. On the top is a cross-sectional view of the holder section 3,while on the bottom is a top view of the holder section 3. Thecross-sectional view shown in FIG. 3 is taken along the dash line A-A′in the upper view. As shown in FIG. 3, the holder section 3 has theinner mask 11 for fixing the optical disk substrate 1 at a positionclose to a central point of the optical disk substrate 1 and the outermask for fixing the optical disk substrate 1 at a position close to aperiphery section of the optical disk substrate 1. Both the inner mask11 and outer mask 12 cover a portion of the optical disk substrate 1,and fix the optical disk substrate 1 holding the optical disk substratebetween it and an upper surface of the holder section 3. Because of thisconfiguration, of a surface of the optical disk substrate 1, onlyportions not fixed by the inner mask 11 and outer mask 12 is afilm-formed section S. In the first embodiment, the radius of the innermask 11 is 20 mm, while the radius of the outer mask is 59 mm.

In the first embodiment, entire rear surface of the film-form section Sand a top surface of the holder section 3 beneath the film-formed area Sare closely contacted to each other, and the upper section of thisholder section 3 is a contact support surface S′. Scopes of thefilm-formed area S and contact support surface S′ are indicated byarrows close thereto respectively. A member (protection member) havinghardness smaller than that of a rear surface of the area 1 of theoptical disk substrate 1 is provided on the contact support surface S′,and as the member is tightly contacted to a rear surface of the opticaldisk substrate 1, generation of damages to a rear surface of the opticaldisk substrate 1 is prevented. A surface which is in the rear sideduring film formation is a surface onto which a light beam is introducedwhen reading out data therefrom. Because of this feature, generation ofdamages to a light beam incidence surface of an optical disk isprevented with the quality improved.

At present, a polycarbonate substrate is often used as the optical disksubstrate 1, so that conceivably a silicon member with the hardnesssmaller than that of polycarbonate is used. FIG. 4 shows a state inwhich a silicon rubber section 15 is provided on a contact supportsurface S′ of the holder section 3.

The optical disk substrate film-formation apparatus according to thefirst embodiment having the configuration as described above forms anoptical disk in the following manner. At first, the optical disksubstrate 1 is fixed by the inner mask 11 and outer mask 12 of thesubstrate holder 6 f as well as vacuum chuck onto an upper surface ofthe holder section 3. The fixed optical disk substrate 1 is carriedthrough the carry-in/carry-out port 20 shown in FIG. 1 into the opticaldisk substrate film-formation apparatus. In this step, a rear surface ofthe optical disk substrate 1 is closely contacted to the contact supportsurface S′.

The substrate holder 6 f is then set to the film-formation chambers 2 ato 2 e successively, and forms each layer such as a dielectric bodylayer, and a storage layer. The conditions for forming the film are asdescribed below:

-   1. ZnS.SiO₂ film (dielectric body layer)    -   Input power: 3 KW    -   Air pressure in the film-formation chamber (Ar gas pressure):        0.27 Pa (2×10⁻³ Torr)-   2. AgInSbTe film (storage layer)    -   Input power: 0.4 KW    -   Air pressure in the film-formation chamber (Ar gas pressure):        0.27 Pa (2×10⁻³ Torr)-   3. ZnS.SiO₂ film (upper dielectric body layer)    -   Input power: 0.4 KW    -   Air pressure in the film-formation chamber (Ar gas pressure):        0.27 Pa (2×10⁻³ Torr)-   4. Al film (Reflection layer)    -   Input power: 9 KW    -   Air pressure in the film-formation chamber (Ar gas pressure):        0.27 Pa (2×10³ Torr)    -   The pressure in this substrate carriage chamber in this step is        0.013 Pa (1×10⁻⁴ Torr).

When film formation is finished, in the optical disk substratefilm-formation apparatus according to the first embodiment, a magneticmember (not shown) for removing the inner mask 11 and outer mask 12 ismoved above the optical disk substrate 1. The inner mask 11 and outermask 12 are attracted to the magnetic member due to magnetism generatedbetween the optical disk substrate 1 and the magnetic member, and isremoved from the holder section 3. In this step, the optical disksubstrate 1 is closely contacted by the vacuum chuck to the contactsupport section S′. A robot for sucking the optical disk substrate (notshown) goes closer to a central section of the optical disk substrate 1with the inner mask 11 and outer mask 12 having been removed therefromto such the optical disk substrate 1 and remove it from the contactsupport surface S′. With the operation described above, the processingsequence executed in the optical disk substrate film-formation apparatusis finished.

In the optical disk substrate film-formation apparatus and optical disksubstrate film-formation method each according to the first embodimentof the present invention, the optical disk substrate 1 is closelycontacted to the contact support surface S′, so that deformation of theoptical disk substrate 1 hardly occurs during film formation. Because ofthis feature, deformation of the optical disk substrate 1 can besuppressed.

The present invention is not limited to the first embodiment asdescribed above. In the first embodiment, a protection member with thehardness smaller than that of the optical disk substrate 1 is provided.However, in place of the configuration as described above, for instance,a step of forming a protection film on a rear surface of the opticaldisk substrate 1 (rear surface protection film formation step) may beprovided before the film formation step. As the rear surface protectionfilm formation step, a step of spin-coating UV hardened resin on a rearsurface of the optical disk substrate 1 may be considered.

Further, a step of previously forming a protection film by sputtering ona rear surface of the optical disk substrate 1 is conceivable. Whenforming a protection film in the way described above, the formedprotection film is any one of a silicon nitride film, a silicon oxidefilm, a titanium nitride film, a film made from compounds of indium,titanium, or oxygen or a laminated film from some of the materialsdescribed above. As described above, when a protection film is formed ona rear surface of the optical disk substrate 1, it is not required toprovide any specific protection member on the contact support surface S′of the holder section 3, and the mother stainless steel (such as astainless) may be used as it is.

Further in the first embodiment, for instance, as shown in FIG. 5, aclaw section 40 for peeling off the optical disk substrate 1 with theinner mask 11 and outer mask 12 having been removed therefrom from thecontact support surface S′ may be provided therein. FIG. 5 shows thesame configuration as that shown in FIG. 3 excluding the claw section40, so that the same reference numerals are assigned to the samecomponents as those shown in FIG. 3, and description thereof is omittedherein. The claw section 40 moves toward a center of an optical disksubstrate as shown in the figure. This movement range is, for instance,from the position shown in the upper cross-section view in FIG. 5 up to2 mm inner from a peripheral section of the optical disk substrate 1 (upto 58 mm on the diameter in the case of an optical disk with a diameterof 60 mm).

The claw section 40 moves up to by 2 mm inside toward the optical disksubstrate 1 with the inner mask 11 and outer mask 12 having been removedtherefrom. In association with this movement, an inclined section 40 aof the claw section 40 goes into a section between a rear surface of theoptical disk substrate 1 and a top surface of the holder section 3, andfunctions to mechanically peel off the optical disk substrate 1 from thecontact support surfaces. Because of this feature, a robot for removingan optical disk substrate can suck the optical disk substrate 1 with arelatively weak sucking force.

With the configuration as described above, it is possible to weaken thesucking force sufficiently adsorbing the optical disk substrate 1 duringfilm formation in the removal step, and even when a thinner optical disksubstrate 1 is used, it is possible to prevent the optical disksubstrate from being broken in the removal step.

A second embodiment of the present invention is described below. In thesecond embodiment, a groove section is provided in the contact supportsurface S′ of the holder section 3 described above. FIG. 6 shows a crosssection of a holder 23 having a groove section according to the secondembodiment (upper view) a top surface thereof (lower view). The crosssection shown in FIG. 6 is taken along the line A-A′ in the lower viewin FIG. 6. The cross-sectional view in FIG. 6 shows a state where theoptical disk substrate 1 is fixed, and the top view shows, now theoptical disk substrate film-formation apparatus 1, but an upper sectionof the holder section 23.

As shown in FIG. 6, the holder section 23 has an inner mask 21 and anouter mask 22 like the holder section 3. A groove section 23 a isprovided on a contact support surface S′ of this holder section 23. Thegroove section 23 a according to the second embodiment has a form inwhich two straight lines crossing each other at right angles at a centerof the holder section 23 and two concentric circles having the samecenter as that of the holder section 23.

With the configuration as described above, in the second embodiment, thecontact support surface S′ and optical disk substrate 1 are partiallyand closely contacted to each other, and the vacuum-chucked optical disksubstrate 1 can be removed with a relatively weak force. Because of thisfeature, the sucking force of the robot for removing an optical disksubstrate can be set to a relatively lower level, and even when theoptical disk substrate 1 is thin, it is possible to prevent the opticaldisk substrate 1 from being broken in the removal step.

The present invention is not limited to the second embodiment describedabove. For instance, any form of the groove section 23 provided on theholder section 23 is allowable on the condition that a proportionbetween an area where the optical disk substrate 1 is closely contactedto the contact support surface S′ and an area in which the optical disksubstrate 1 is off from the latter is appropriate.

The optical disk substrate film-formation apparatus according to thethird embodiment of the present invention has, like the optical disksubstrate film-formation apparatus according to the first embodimentdescribed above, a substrate carriage chamber 10 and at least afilm-formation chamber 2 a, and a substrate holder is positioned betweenthe substrate carriage chamber 10 and film-formation chamber 2 a.Further, a through-hole communicating to the substrate carriage chamber10 as well as to the film-formation chambers 2 a to 2 e is provided(Description of the third embodiment assumes that the optical disksubstrate film-formation apparatus has film-formation chambers 2 a to 2e, and through-holes are provided in all of this substrate holders).Further, a pressure in each of the film-formation chambers 2 a to 2 e inwhich film formation is being executed is kept higher than that in thesubstrate carriage chamber.

The third embodiment of the present invention is described below. FIG. 7shows a cross section of the holder section 33 having a through-hole 33a according to the third embodiment (upper view) and a top sectionthereof (lower view). The cross section shown in the lower view is takenalong the line A-A′ in the lower view. In FIG. 7, the cross-sectionalview shows a state in which the optical disk substrate 1 is fixed, andthe top view shows not the optical disk substrate 1, but a top sectionof the holder section 33.

As shown in FIG. 7, the holder section 33 has an inner mask 33 and anouter mask 32. Through-holes 33 a are provided in the contact supportsurface S′ of the holder section 33. The through-holes 33 a according tothe third embodiment are provided in the radial directions as shown inthe top view in FIG. 7, and edges in one side thereof are connected tothe film-formation chambers 2 a to 2 e, while the other edges thereofare connected to the substrate carriage chamber 10.

In the optical disk substrate film-formation apparatus according to thethird embodiment having the configuration as described above, theoptical disk is formed in the following manner. At first, the opticaldisk substrate 1 is fixed with the inner mask 31 and outer mast 32 ofthe substrate holder 6 f to a top surface of the holder section 33. Theoptical disk substrate is then carried into the optical disk substratefilm-formation apparatus from the carry-in/carry-out port 20 shown inFIG. 1. In this step, portions of the optical disk substrate 1 excludingthe through-holes 33 a are tightly contacted to the contact supportsurface S′ of the holder section 33.

In the next step, the substrate holder 6 f is successively set to thefilm-formation chambers 2 a to 2 e, and each film is formed on theoptical disk substrate 1 fixed to the substrate holder 6 f under theconditions for film formation as described in the first embodiment. Thefilm-formation conditions described in the first embodiment include apressure in each of the film-formation chambers 2 a to 2 e of 27 Pa(2×10⁻³ Torr). On the other hand, a pressure in the substrate carriagechamber 10 is 0.013 Pa (1×10⁻⁴ Torr). Therefore, the optical disk 1 istightly contacted to the contact support surface S′ excluding thethrough-holes 33 a due to the pressure difference during the filmformation.

With the configuration as described above, in the third embodiment, theoptical disk substrate 1 can tightly be contacted to the holder section33 during film formation without using vacuum chuck. Because of thisfeature, even in the environment not using a vacuum chuck, the opticaldisk substrate film-formation apparatus according to the presentinvention can be used, which improves convenience in use of the opticaldisk substrate film-formation apparatus. In addition, there is no needof providing a dedicated vacuum chuck so that the configuration of theoptical disk substrate film-formation apparatus is simplified.

Because of the features as described above, vacuum chuck for the opticaldisk substrate 1 disappears without the need of controlling for releaseof vacuum chuck immediately when film formation is finished. Therefore,even when the optical disk substrate 1 is thin, it is possible toprevent the optical disk substrate 1 from being broken in the removalstep.

The present invention is not limited to the third embodiment describedabove. For instance, any location and form of the through-holes 33 aprovided in the holder section 33 are allowable on the condition that aproportion of an area where the optical disk substrate 1 closely contactthe contact support surface S′ and an area where the former is off fromthe latter is acceptable.

Examination of Results in the First to Third Embodiments:

Inventors of the present invention carried out testing for filmformation using the optical disk substrate film-formation apparatusesand the optical disk substrate film-formation method as described above.The inventors measured the maximum warping amount of each substrate toverify the effect obtained in each of the embodiments. The maximumwarping amount as defined herein indicates a warping amount of a portionwhich warps most in an optical disk substrate on which a film has beenformed. The warping amount is defined in some cases with an anglebetween an ideal surface of an optical disk substrate and a tangent to asurface of the actual optical disk substrate (described as the maximumwarping angle), and in other cases with a positional difference asexpressed in term of length between an ideal surface of an optical disksubstrate and a surface of the actual optical disk substrate (describedas maximum warping amount hereinafter).

1. Examples of the Maximum Warping Angle

Optical disk substrate on which a film is formed with the optical disksubstrate film-formation apparatus and method based on the conventionaltechnology: 4 degrees

Optical disk substrate on which a film is formed with the optical disksubstrate film-formation apparatus and method according to the firstembodiment: 0.6 degree (Contact support surface: Silicon rubber, norprotection film on a rear surface thereof), or 0.5 degree (Contactsupport surface: stainless, Protection film on a rear surface thereof:UV hardened resin)

Optical disk substrate on which a film is formed with the optical disksubstrate film-formation apparatus and method according to the firstembodiment: 0.5 degree (Contact support surface: stainless, protectionfilm on a rear surface thereof: UV hardened resin)

Optical disk substrate on which a film is formed with the optical disksubstrate film-formation apparatus and method according to the thirdembodiment: 0.5 degrees (Contact support surface: stainless, protectionfilm on a rear surface thereof: UV hardened resin)

2. Examples of the Maximum Warping Amount

FIG. 8 shows a result of testing on film formation on optical disksubstrates having thickness of 1.2 mm, 0.7 mm, and 0.3 mm with theoptical disk substrate film-formation apparatuses and methods accordingto the first to third embodiments of the present invention to comparethe maximum warping amount obtained in the testing to that obtained whenfilm formation is performed on optical disk substrates having the samethickness with optical disk substrate film-formation apparatus andmethod based on the conventional technology. FIG. 9 is a graph showingthe relation between the maximum warping amount and thickness of eachoptical disk substrate shown in FIG. 8. The third embodiment {circlearound (3)}-1 is different from the third embodiment {circle around(3)}-2 in its shape of a holder, and the third embodiment {circle around(3)}-1 corresponds to a case where the holder section 23 shown in FIG. 6is used, and the third embodiment {circle around (3)}-2 shows a casewhere the holder 33 shown in FIG. 7 is used.

In FIG. 8 and FIG. 9, the maximum warping amount in an optical disksubstrate with the thickness of 0.6 mm used for an adhesion type ofoptical disk is 500 μm, and that when film formation is performed withthe present invention is in a range from 290 to 300 μm, so that themaximum warping amount clearly decreases to one half. In the process ofmanufacturing the adhesion type of optical disks, a substrate with afilm having been formed thereon is adhered to another one in thepost-processing step to correct the warp. In the case of a substratewith the maximum warping amount of 550 μm, it is difficult to reduce thewarp to a level required to satisfy the requirements for the product.With the present invention, the maximum warping amount is in a rangefrom 290 to 300 μm, and it is fully possible to reduce the warpingamount by means of adhesion to the allowable range.

Further, with the first to third embodiments of the present invention,even in the case of a substrate having thickness of 0.6 mm or less, itis possible to reduce the maximum warping amount to less than 400 μm. Asdescribed above, with the present invention, it is possible to realizean adhesion type of optical disks using a substrate having the thicknessof 0.6 mm or less.

FIG. 10 shows a cross section of a substrate holder 201 according to thefourth embodiment in a state where the substrate holder 201 is holdingan optical disk substrate 221. FIG. 11 is a top view of the substrateholder shown in FIG. 10, and shows a state before the substrate holder201 holds the optical disk substrate 221. In FIG. 10 and FIG. 11, thereference numeral 202 indicates an outer mask, while the referencenumeral 203 indicates an inner mask. Entire surface of this substrateholder 202 contacting a rear surface of the substrate 221 is subjectedto the processing for roughing by sand blast machining, and the surfaceroughness Rmax of this roughed section (rough surface section) is in arange from 40 μm to 50 μm.

A polycarbonate substrate with the thickness of 0.6 mm obtained by meansof injection molding is used as the optical disk substrate 221 and isheld with the substrate holder 201. This holder is set in a sputteringfilm-formation apparatus and a ZnS.SiO₂ layer, AgInSbTe layer, and Allayer are formed as a dielectric body layer, a recording layer, and areflection layer respectively.

When forming a film, the substrate 221 is placed on the substrate holder221, a central portion of the substrate 221 is fixed with the inner mask203, a peripheral portion of the substrate 221 is fixed with the outermask 202, and thus a desired thin film is formed by sputtering. In thistesting, a total film thickness after film formation is in a range from350 to 400 μm.

Examples 1, 2 for Comparison

As substrate holders for comparison, (1) a substrate holder 211 based onthe conventional technology shown in FIG. 12, and (2) a substrate holder(not shown) with the entire surface of the substrate holding surfacemachined to a flat plane (not subjected to the roughing processing)which holds a substrate in a state where the substrate holder closelycontacts the entire rear surface of the substrate 221 are prepared assubstrate holders for comparison, and a desired thin film is formed bysputtering under the same conditions as those in the fourth embodiment.The result of comparison between the fourth embodiment and the examples1, 2 for comparison is shown in Table 1. In FIG. 12, designated at thereference numeral 212 is an outer mask, at 213 an inner mask, at 214 agroove, and at 221 an optical disk substrate.

TABLE 1 Structure of a Warp of a substrate Situation of taking holder(Inclination angle) out a substrate Substrate holder based Measurementimpossible A substrate can on the conventional (Large deformation)smoothly be taken technology out. (Refer to FIG. 12) Substrate holder0.5 to 1 degree A substrate is contacting a tightly adhered to asubstrate holder, and can not (Contacting an be taken out entiresurface) smoothly. Substrate holder 0.5 to 1 degree A substrate canaccording to the smoothly be taken present invention out. (Refer to FIG.10 and FIG. 11)

As clearly shown in Table 1, deformation of a substrate can besuppressed by applying the present invention, and in addition asubstrate can smoothly be carried out from a substrate holder. As aresult, with the present invention, high quality film-formed substrates(without any warp) can be manufactured at high productivity (excellentadaptability for being carried out). On the contrary, in the case ofsubstrate holders in the examples 1 and 2, a substrate is largelydeformed, or can not smoothly be carried out from a substrate holder. Alarge warp is observed, although the adaptability for being taken outfrom a substrate holder is excellent, in the substrate holder shown inFIG. 12 because a groove is provided thereon.

A substrate holder with the surface roughness Rmax in a range from 40 μmto 50 μm is prepared by roughing a portion of or entire surface of thesubstrate holding surface by means of sand blasting and further byexecuting organic plating with triazinethiol to this roughed surface.The organic plating is executed, like in the ordinary plating withmetal, in an electrolytic solution, and in this process not a metallicfilm, but a triazinethiol organic film is formed. In this processingwith triazinethiol, it is possible to control only a thickness of thefilm with high precision, and in addition the adaptability forlubrication and water-repelling performance which can not be achieved ina metallic film can be obtained. Therefore, with a facility similar tothat used for metallic plating, an organic film made from triazinethiolcan easily be prepared. With this feature, there are provided theadvantages not only that it can be manufactured with relatively lowcost, but that it can hardly be peeled off even at a high temperature.

The fifth embodiment is explained below. The substrate holder accordingto the fifth embodiment of the present invention is subjected to theroughing processing and the processing for lubricating a surface thereofwith a triazinethiol organic film, in addition to the effect ofpreventing warping of a substrate, the following effects are obtained;(1) the adaptability for being smoothly taken out (stability andeasiness in the removal step) is further improved as compared to aholder subjected to the roughing processing, and (2) damages to a rearsurface of a substrate taken out are reduced. It is conceivable that theeffects (1) and (2) are realized because the adaptability for beinglubricated is given to a substrate holding surface of the substrateholder.

The sixth embodiment is explained below. A portion of a substrateholding surface of a substrate holder is made from PTFE like in thefourth embodiment. For that purpose, a PTFE plate with one surfacethereof previously roughed by sand blasting is manufactured, and thePTFE plate is adhered to a specified portion of the substrate holder.Although a substrate holder and a mask used in a sputter device aregenerally made from metallic material, in this embodiment, by formingonly a portion contacting a substrate with a plastic material having theexcellent self-lubricating capability, it is possible to prevent damagesto the substrate. As a result, the effects of preventing warping of asubstrate, improving the adaptability when being taken out, and reducingthe possibility of damage of the substrate are obtained like in thefourth embodiment. POM (polyacetal) resin or the like may be used in thePTFE. Further, by using a self-lubricating plastic material in a portionof a substrate holder, desired effects can be obtained without largelychanging structure and specification of the substrate holder. Namely byusing an expensive material only in a required portion of a substrateholder and also by using a metallic material in other sections thereof,a holder according to the present invention can be realized withoutcausing const increase.

The fourth and fifth embodiments of the present invention are describedabove, but no problem occurs even when such parameters as surfaceroughness are made larger within a range where no deformation of asubstrate occurs. Application of the present invention is not limited toa substrate holder for a device to process an optical disk substrate bysputtering, and the present invention can successfully be applied also asubstrate holder for executing the sputtering processing to varioustypes of substrate with a small thickness which are easily deformed.

FIG. 13 is a general flat view showing the seventh embodiment of thepresent invention. Reference numeral 301 indicates a substrate holder,reference numeral 302 indicates a substrate for an optical recordingmedium, reference numeral 303 indicates a center hole section, referencenumeral 304 indicates a porous section, and reference numeral 305indicates a groove section. FIG. 14 is a partial view showing a generalcross sections of the substrate holder 301 and a substrate 302 of anoptical recording medium set in the substrate holder 301 in the seventhembodiment. FIG. 15 is a view showing an example of a form of the porousmember 304 used in a substrate holder according to the presentinvention, and the reference numeral 304 p in the figure indicates aplane section thereof.

In this seventh embodiment, the groove section 305 is provided in thesubstrate holder 305, and the gas-permiable porous member 304 isprovided in the groove section 305. The groove section 305 extends frominside of an area where the substrate holder 305 contacts a substrate302 to an area in which the substrate holder 305 does not contact thesubstrate, and the porous member 304 has an area where the membercontacts the substrate 302 and an area in which the member is exposed ina space in a vacuum vessel. In this step, a surface of the porous member304 is adjusted to the same level as a surface of the substrate holder301.

FIG. 16 is a flat view showing a general configuration of a key sectionin the eighth embodiment of the present invention. FIG. 17 is a partialcross-sectional view showing a general configuration of the substrateholder 301 and the substrate 302 of an optical recording medium loadedon the substrate holder 301.

In this eighth embodiment, the groove section 305 is provided in aportion contacting a surface of the plastic substrate 302 in which afilm is not formed thereon, and the porous member 304 is positioned inthe groove section 305. In addition, a through-hole 306 having a smallerarea than that of the porous member 304 is provided on a rear surface ofthe porous member 304. The area of this through-hole 306 is smaller thanthe area of the porous member 304 so as to insure a surface for stablingholding the porous member 304.

In the seventh and eighth embodiments, a surface of the porous member304 has the same height as that of a surface of the substrate holder 301in which the substrate holder 301 contacts a substrate. With theconfiguration as described above, deformation of the plastic substrate302 is prevented, further, air can easily pass through the memberbecause it is porous, so that it is possible to prevent troubles incarriage (such as failure of a transport robot in taking up thesubstrate 302 or deformation of the robot arm associated with thefailure) air-tight contact (vacuum adsorption) between the substrateholder 3-1 and substrate 302 in the step of taking out a substrate.

Preferably the porous member 304 is made from a material with highconductivity so that temperature distribution will not occur inside thesubstrate holder 301 due to thermal energy received by the substrateholder 301. Further, it is preferable to prevent the generation ofminute damages on the surface of the substrate. Therefore, the porousmaterial is formed from a material with a polymeric material coated onthe surface thereof or from an elastic material.

The porous member 304 can be obtained by molding particles by means ofhot forming or press forming under the room temperature, and thegas-permeability is realized because of a continuous space betweenparticles. A material with high thermal conductivity which can be usedas a material for this porous member 304 is preferably a relatively softmetal ball with a small diameter and having excellent thermalconductivity made from such metals as Ag, Au, Cu, Al, Mg, or brass. Whenthe metal ball is used as it is, contact between the metal balls and thesubstrate 302 is a point contact because of the shape of ball, and thecontact is not stable. Therefore, it is preferable to mold the metalballs by pressing (under the room temperature) or by hot pressing forforming a flat section 304 p in a portion of every ball. The flatportion should be formed only on a surface contacting the substrate 302,and the porous member 304 may be cut to form a flat section thereon.

As a polymeric material or an elastic material used for the porousmember 304, when uniformity of temperature distribution in the substrateholder 301 can be maintained (for instance, within ±5 degree centigrade,a single material may be used, but when the uniformity can not bemaintained, it is better to use a mixture of several materials with highelectric conductivity or excellent thermal conductivity for the porousmember 304. The materials with high electric conductivity or excellentthermal conductivity suited for mixing include inorganic conductivematerials such as fine particles of Ag, and powder of black lead, andorganic conductive materials such as tetrafluoroborate or tetra-n-butylammonium.

Example of substrate holder according to the seventh and eighthembodiments of the present invention are described below.

EXAMPLE 1

Spherical copper particles each having a diameter of about 0.5 to 1 mmare molded to prepare the porous material 304 by loading a pressurethereon so that a void will be formed by 10 to 40 volumetric percent andalso so that the molded member will place itself into a rectangulargroove section 305 with the depth of 2.0 mm, width of 10 mm, and lengthof 30 mm formed on a plastic plane substrate set surface of thesubstrate holder 301. This porous member 304 is set in the groovesection 305 so that a surface thereof is included in the same plane asthe substrate set surface of the substrate holder 301. A polycarbonatesubstrate 302 for an optical disk with the size of 120 φ and thicknessof 0.6 mm is set on the substrate holder 301 obtained as describedabove. The rectangular groove section 305 is positioned so that a lengthof an area contacting a rear surface of the substrate 302 is around 20mm and a length of an area off from the substrate 302 is around 10 mm. Astainless-steel mask is positioned in the front surface side of theporous member 304 in the area off from the substrate 302 so that thesubstance used for film formation will not directly be depositedthereon.

Using the substrate holder 301 described above, a first dielectric bodylayer with the thickness of around 150 nm, a recording layer with thethickness of around 30 nm, a second dielectric body with the thicknessof around 20 nm, and a reflection layer with the thickness of around 60nm are successively formed in a vacuum. Temperature of the substrate 302for an optical disk increases on its film-formation surface to a rangefrom 110 to 125 degree centigrade, but temperature distribution in thesubstrate holder 301 is within ±2 to 3 degree centigrade even after 1000sheets of substrate are manufactured, and mechanical deformation of thesubstrate 203 does not occur. No trouble occurs during carriage of asubstrate in the vacuum device. Further, a result of assessment ofperformance of the optical disk showed that degree of tilt in the radialdirection and in the tangential direction are +0.40 degree, +0.15 degreerespectively, and no signal fault is observed when data is deleted.

EXAMPLE 2

Spherical copper particles each having a diameter of about 0.5 to 1 mmare molded to prepare the porous material 304 by loading a pressurethereon so that a void will be left by 10 to 40 volumetric percent andalso so that the molded member will place itself into a rectangulargroove section 305 with the depth of 1.5 mm, width of 10 mm, and lengthof 20 mm formed on a plastic plane substrate set surface of thesubstrate holder 301. This porous member 304 is set in the groovesection 305 so that a surface thereof is included in the same plane asthe substrate set surface of the substrate holder 301. Dimensions of therectangular groove sections 305 are set in such a manner that, when thesubstrate holder 301 for an optical disk is set on the substrate holder301, the groove section 305 is completely covered with the substrate302. In addition, a rectangular through-hole 306 with the width of 5 mmand length of 10 mm is formed at a center of the groove section in thesubstrate holder 301. When films made from various materials are formedon a substrate for an optical disk in the completely same operatingsequence as that in Example 1, an excellent result similar to that inExample 1 can be obtained.

EXAMPLE 3

A small quantity of adhesive polymeric material with black lead powdermixed therein (For instance, an alkyl-based coating agent containing acarbon filler: Dotite XC12 produced by Fujikura Kasei) is coated on asurface of cupper particles or plastic particles each having a diameterof about 0.5 to 1 mm to form the porous member 304, and then testing isexecuted like in Examples 1 and 2 using the porous member 304 solidifiedto the same dimensions as those in Examples 1 and 2. A result ofassessment of thermal deformation and performance thereof as an opticaldisk is excellent like in Example 1.

EXAMPLE FOR COMPARISON 3

Using a holder with four through-holes each with the size of 10 φ, filmsmade from various materials are formed on a substrate for an opticaldisk under the same conditions for film formations as those in theexamples described above. Temperature of the substrate rises up to arange from 110 to 125 degree centigrade. In this step, mechanicaldeformation is observed. However, as the through-holes are provided,failure in taking out a substrate after film formation does not occur.Further the performance as an optical disk is assesses, and degrees oftilt in the radial direction or in the tangential direction is in arange from ±1.20 to 2.50 degree or more, and ±0.70 to 2.50 degree ormore, and no abnormality is observed in deleting recorded data.

EXAMPLE FOR COMPARISON 4

Using a substrate holder with four through-holes each with the size of10 φ, films from various types of material are formed on a substrate foran optical disk under the same conditions for film formation as thoseemployed in the examples described above. Temperature of the substratesimilarly rises to a range from 110 to 125 degree centigrade. Mechanicaldeformation of a substrate is observed in this step. However,through-holes are provided in the substrate, no failure occurs in takingout a substrate after film formation. Further the performance as anoptical disk is assessed, and degrees of tilt in the radial directionand tangential directions are ±1.20 to 2.50 degree or more, and ±0.70 to2.50 degree or more respectively, and no failure occurs in deletingrecorded data.

EXAMPLE FOR COMPARISON 4

A plane holder not having any through-hole nor a groove section thereinis used as a substrate holder, and films made from various types ofmaterial are formed on a substrate for an optical disk under the sameconditions for film formation like those in the examples describedabove. Increase of temperature is like that in the Example 3 f orcomparison, but in this step, mechanical deformation is not observed. Inthe assessment of performance as an optical disk, the same result asthat in Example 1 is obtained. However, failure in taking up a substrateoccurs at the probability of around 10% because air-tight adsorptionoccurs on a substrate.

FIG. 18 shows general configuration of a key section of an optical disksubstrate film-formation apparatus according to the ninth embodiment ofthe present invention. In FIG. 18, designated at the reference numeral401 is a substrate holder, designated at 401 a is a substrate holdingsection which is a portion of a rear surface of a substrate where a filmis formed thereof and the substrate holder contacts the substrate,designated at 402 is an inner mask, designated at 403 is an externalmask, designated at 404 is a substrate, and the sign Win indicates awidth from an outer-side edge of the internal mask 402 to an inner sideedge of the substrate holding section 401 a, while the sign Woutindicates a width from an inner-side edge of the outer mask 403 to anouter-side edge of the support holding section 401 a. The inner mask 402having a diameter of 41 mm is used. Further, the outer mask 403 coveringfrom the utmost outer periphery of the substrate 404 up to 0.5 mm innertherefrom is used. A range C in which a rear surface of the substrate404 contacts the substrate holder 401 is from a position by 4 mm outerfrom an outer edge of the inner mask 402 to a position by 1 mm innerfrom an inner edge of the outer mask (namely, Win=4 mm, and Wout=1 mm).

Optical disks each having the configuration shown in FIG. 21 areprepared by using the structure as described above. Any of the opticaldisks is manufactured by the RF magnetron sputter method, and theso-called sheet type of sputter device is used. For comparison, anoptical disk is manufactured with a substrate holder having thestructures shown in FIG. 19 and FIG. 20 under the same conditions. Thesubstrate holder shown in FIG. 20 has the configuration like that in theconventional technology, and as the substrate holder 401 contacts anentire rear surface of the substrate 404, influence over warping of asubstrate is small, but a trouble may easily occur during transportationof the substrate.

A result of comparison of warping amounts of these disks is shown inFIG. 22. The warping amount is shown as a positional difference at 58 mmin the radial direction between before and after film formation. As aresult, in the present invention, a disk showing the same warping amountas that in the configuration shown in FIG. 20 is obtained.

Samples No. 1 to No. 14 are prepared not by changing the form of thesubstrate holder shown in FIG. 18, but by changing the dimensions of Winand Wout as shown in FIG. 23. Film formation is carried out on thesamples (sample No. 1 has the same configuration as that in the ninthembodiment) under the same conditions as those in the ninth embodiment,and a warping amount of each substrate and a number of substrates whichare not loaded on or of f to and from a substrate holder when filmformation is executed continuously. From the result shown in FIG. 23, itis understood that, to suppress the warping amount of the substrate to alevel of around 100 μm and also to smoothly execute operation of loadingon or off the substrate, the substrate holding section of the substrateholder has to be contacted to the substrate under the condition that Winis between 2 to 10 mm and Wout is between 0.5 to 5 mm.

FIG. 25 is a partial view showing a general configuration in theeleventh embodiment of the present invention. In this embodiment, anedge section 401 e of a substrate holding section 1 a of the substrateholder used in the ninth embodiment and shown in FIG. 18 is tapered. Assamples of substrate holder having the tapered form as described above,samples No. 15 to No. 21 are formed as shown in FIG. 24, and each of thesamples is assessed by executed film formation thereon under the sameconditions as those in the ninth embodiment. Further, a surface of thesubstrate in which the substrate 404 and edge section 401 e contact toeach other is observed with a microscope. The taper angle θ of thetapered section is defined herein as an angle between a surface of thesubstrate holder 401 contacting a substrate and a tapered surface t ofthe tapered section.

As understood from the result shown in FIG. 24, when the taper angle θof the edge section is between 0 to 0.5 degree, generation of damages ina portion of a substrate with a film formed thereon is observed, andwhen the angle is 1.0 degree or more, no damage is observed. As fordeformation (warping amount) of a substrate, when the taper angle θ isbetween 0.5 to 2.0 degree, the warping amount is 100 μm like that when atapered form is not introduced (when the taper angle is 0 degree), butwhen the taper angle is 2.5 degree, the warping amount increase to 150μm, and when the taper angle is 3.0 degree, the warping amount furtherincreases to 200 μm. Therefore, by giving a taper angle θ in a rangefrom 1.0 to 2.0 degree, a warping amount of a substrate can be reduced,and further generation of damages to a substrate caused by the edgesection 401 e of the substrate holder can be prevented.

FIG. 27 shows a general configuration in the twelfth embodiment of thepresent invention. In this embodiment, a silicon rubber member 405 witha width H is provided in the edge section 401 e having the configurationused in the ninth embodiment described above and shown in FIG. 18. Thewidth H is defined herein as a length of the silicon rubber member 405in the radial direction of the substrate 404 as shown in FIG. 27. Withthe configuration shown in FIG. 27, samples of substrate holder No. 22to No. 27 are manufactured as shown in FIG. 26, and firm formation isperformed on each of the samples under the same conditions as those inthe eleventh embodiment, and assessment is carried out. As shown in FIG.26, with the configuration according to this embodiment, a warpingamount of a substrate can be suppressed to around 100 μm, and alsodamages to a substrate by the edge section 401 e of the substrate holdercan be prevented. When the width H of the silicon rubber member is lessthan 0.1 mm, mechanical load to the edge section 401 e due todeformation of a substrate can not be evaded, and when the width H is0.5 mm or more, suppression of deformation of a substrate can not beexpected. Although a silicon rubber member is used for the edge section401 e in this embodiment, the effects obtained in this embodiment arenot limited to the one obtained when the silicon rubber is used, and anymaterial such as a molded resin body may be used so far as the hardnessis lower than that of a substrate.

FIG. 28 shows a cross section of a load lock chamber in a generaloptical disk substrate film-formation apparatus according to thethirteenth embodiment. Designated at the reference numeral 501 is asubstrate, designated at 502 is a stack ring, designated at 503 is aninner mask, designated at 504 is an outer mask, designated at 505 is anelectric magnet. Designated at 506 is a substrate holder for carrying asubstrate to outside of an optical disk substrate film-formationapparatus (described as a substrate for outward carriage hereinafter).Designated at 507 is a substrate holder for carrying a substrate toinside of the optical disk substrate film-formation apparatus (describedas a substrate holder for inward carriage). Designated at 508 is an armfor carrying a substrate into an optical disk substrate film-formationapparatus. Designated at 509 is a magnet, 501 is an O-ring, and 511 is aload lock chamber. In this thirteenth embodiment, an optical disksubstrate film-formation apparatus having the configuration as shown inthe figure is described, but the present invention is not limited tothis configuration.

With respect to the optical disk substrate film-formation apparatusaccording to the present invention, a substrate holder section in whichthe present invention is applied is shown in FIG. 29. Designated at thereference numeral 522 is a gas supply port in the side of a frame of theoptical disk substrate film-formation apparatus (described as frame-sidegas supply port hereinafter). Designated at 523 is a gas supply path inthe side of a frame of the optical disk substrate film-formationapparatus (described as frame-side gas supply path), designated at 524is a substrate holder-side gas supply port, and designated at 525 is asubstrate holder-side gas supply path.

At first, the step of carrying into or out a substrate from an opticaldisk substrate film-formation apparatus is described below withreference to FIG. 28. The substrate 501 is placed on an inner mask 503and an outer mask 504 magnetically attached to an electric magnet 505 ina substrate holder 506 for outward carriage, and is carried to a loadlock chamber 513. In this step, a closed space for the load lock chamber513 is formed by the substrate holder 506 for outward carriage,substrate holder 507 for inward carriage, and frame 511 of the opticaldisk substrate film-formation apparatus. The electric magnet 505 for thesubstrate holder 506 for outward carriage is then turned OFF, and theinner mask 503, outer mask 504, and substrate 501 are magnetically fixedby the magnet 509 provided on the substrate holder 507 for inwardcarriage, and are carried out from the optical disk substratefilm-formation apparatus.

By making a substrate holder based on the structure shown in FIG. 29,the problem of vacuum adsorption between a substrate and a substrateholder in carrying out a substrate from an optical disk substratefilm-formation apparatus can be solved.

In FIG. 29, in a state where the substrate holder 507 for inwardcarriage is located at a specified position in the load lock chamber513, the frame-side gas supply path 523 is communicated to the substrateholder-side gas supply path 525. This linkage is realized by linking theframe-side gas supply path 523 and the substrate holder-side gas supplypath 525 with the O-ring or the like for insuring air-tightness, or bylinking the two sections without air-tightness. As the method to insurethe air-tightness, in addition to the method described above, variousmethods including a method of giving a taper are available. Thedifference between communication with air-tightness and communicationwithout air-tightness is described later.

FIG. 29 shows communication without air-tightness. The configuration isdescribed below. Substrate holder-side gas supply ports 524 are holeseach having a diameter of 2 mm, and three holes are provided in theradial direction in each quadrant, and one of the three holes isprovided in the stack-ring preventing groove 512. Positions of thesubstrate holder-side gas supply ports are limited within an area wherea substrate covers a substrate holder. There is no restriction over aform, location, size, and a number of the substrate holder-side gassupply ports 524, nor is restriction over a form of the substrateholder-side gas supply path 525. R machining of 0.5 mm is provided on anedge section of each substrate holder-side gas supply port 524. Thevalue of R machining is not limited to that described above, and anappropriate value may be employed according to size, position, or otherparameters of the substrate holder-side gas supply port 524. Byproviding the R machining, damages caused by contact between thesubstrate holder-side gas supply port 624 and a rear surface of asubstrate can be reduced. In addition, by lubricating a surface of asubstrate holder, damages to a rear surface of a substrate can furtherand substantially be reduced.

In this thirteenth embodiment, triazine is used for lubrication of asurface of a substrate holder, the material for lubrication is notlimited to triazine, and complex plating with water-repelling powder ofcarbon fluoride (CF)n or fluororesin (PTFE, PFE, FEP) or the processingfor water repulsion using a chlorosilane-based chemical adsorbent isalso effective.

With the configuration described above, after film formation bysputtering is finished, when the substrate holder 507 for inwardcarriage returns to a specified position in the load lock chamber 513,the frame-side gas supply path 523 and substrate holder-side gas supplypath 525 are communicated to each other. In the next step, inside of theload lock chamber is ventilated, and the substrate is vacuum-chucked tothe substrate holder, but by supplying nitrogen from the frame-side gassupply path 523 via the substrate holder-side gas supply path 525 to thesubstrate holder-side gas supply port 524, the substrate is easilyseparated from the substrate holder, and can be carried by the substrateholder 506 for outward carriage to outside of the optical disk substratefilm-formation apparatus. In this step, a pressure of supplied gas is1.1×10⁵ Pa (1.1 bar), but any level of pressure may be used so long asthe pressure is higher than the atmospheric pressure. Further, thesupplied gas is not limited to nitrogen gas, and any gas may be used onthe condition that the gas is not dangerous.

In this testing, the gas supplied from the frame-side gas supply path523 via the substrate holder-side gas supply path 525 to the substrateholder-side gas supply port 524 was also used for ventilating inside ofthe load lock chamber 513, and in that case, the substrate was notvacuum-chucked to a substrate holder, and could be carried out by thesubstrate holder 506 for outward carriage to outside of the optical disksubstrate film-formation apparatus. The pressure of supplied gas used inthis step is set to 0.1×10⁵ Pa (0.1 bar) in the initial stage, and thento 1.1×10⁵ Pa (0.1 bar) in 0.5 second, but the pressure level is notlimited to these values. As compared to a case where the gas is not usedfor ventilation of inside of the load lock chamber, the sufficienteffect of separating a substrate from a substrate holder can be obtainedeven at a low pressure level of supplied gas, which is specific to thismethod.

A difference between a case where the frame-side gas supply port 522 andsubstrate holder-side gas supply path 525 are communicated withair-tightness and a case where the two sections are communicated to eachother without air-tightness is described below.

At first, the case where the two sections are communicated withair-tightness is explained. When the load lock chamber 513 is evacuated,the frame-side gas supply path 523 and substrate holder-side gas supplypath 525 can not be evacuated with a pump for evacuating the load lockchamber, so that another mechanism for evacuation is provided forventilating the gas supply paths. FIG. 30 shows one example of suchconfiguration, and shows only a section corresponding to the section Cin FIG. 29. The reference numeral 530 indicates a bypass valve.

By opening the bypass valve 530 provided between the frame-side gassupply path 523 and load lock chamber 513 when the load lock chamber isto be evacuated, not only the load lock chamber 513, but also theframe-side gas supply path 523 and substrate holder-side gas supply path525 are simultaneously evacuated. After the evacuation, the bypass valve530 is closed, and a substrate with a film having been formed thereon bysputtering is carried to the load lock chamber 513, when the frame-sidegas supply path 525 and substrate holder-side gas supply path 525 arecommunicated to each other with air-tightness and gas for releasingvacuum check of the substrate to the substrate holder is supplied fromthe air-tight flow path.

Another method is to provide a separate evacuation path for theframe-side gas supply path 523 as shown in FIG. 31. FIG. 31 shows only aportion of the evacuation path corresponding to the section C in FIG.29. Designated at the reference numeral 531 is an evacuation valve for agas supply path, and designated at 532 is a vacuum pump. Operations ofthis evacuation valve for a gas supply path are the same as those of thebypass valve 530 described above. A vacuum pump 532 may be used incombination with a pump for evacuation of the load lock chamber 513.With such a configuration, mechanism of the apparatus becomescomplicated, but the frame-side gas supply path 523 and substrateholder-side gas supply path 525 are used also as a shielded flow pathcommunicating to a rear surface of a substrate, and a large effect canbe obtained in vacuum-chucking a substrate to a substrate holder.

When the communication is realized without air-tightness, when the loadlock chamber is evacuated, sufficient evacuation is carried out from alinkage section between the frame-side gas supply port 522 and thesubstrate holder-side gas supply path 525, so that it is not necessaryto provide a separate evacuation system for the frame-side gas supplypath 523 and substrate holder-side gas supply path 525, which makes itpossible to simplify the configuration of the apparatus. On thecontrary, it is required to raise the pressure of supply gas forseparating a substrate from a substrate holder, but this problem caneasily be solved, and causes no trouble in achieving the effect specificto the present invention.

Although not shown in the figure, a valve which closes when the loadlock chamber is evacuated is required in the upstream section from theframe-side gas supply path 523 regardless of whether the communicationis realized with or without air-tightness. When an evacuation speed inthe load lock chamber is taken into considerations, it is preferable tolocate the valve at a position as close to the frame-side gas supplypath 523 as possible.

FIG. 32 shows configuration of a substrate holder section used in anoptical disk substrate film-formation apparatus according to thefourteenth embodiment of the present invention. Reference numeral 514indicates a groove section. In FIG. 29, a flow path for gas to be flownfrom the substrate holder-side gas supply port 524 is terminated in aclosed space formed by a substrate and a substrate holder, but in FIG.32, the substrate holder-side gas supply port 524 is provided in an openspace between a substrate and a substrate holder. The basicconfiguration is the same as that shown in FIG. 29, so that detaileddescription thereof is omitted herein, and only operations specific tothis embodiment are described herein.

In the example shown in FIG. 32, like in FIG. 29, when film formation bysputtering is finished and the substrate holder 507 for inward carriagereturns to a specified position in the load lock chamber 507, theframe-side gas supply path 523 and substrate holder-sided gas supplypath 523 are communicated to each other. When inside of the load lockchamber 513 is ventilated, a substrate is vacuum-chucked to a substrateholder, but by supplying nitrogen gas from the frame-side gas supplypath 523 via the substrate holder-side gas supply path 525 to thesubstrate holder-side gas supply port 524, the substrate is easilyseparated from the substrate holder, and can be carried out by thesubstrate holder 506 for outward carriage to outside of the optical disksubstrate film-formation apparatus.

Different from FIG. 29, FIG. 30 shows a case in which the mechanismshown in FIG. 30 and FIG. 31 for evacuating the frame-side gas supplypath 523 and substrate holder-side gas supply path 525 is not requiredfor evacuation of the load lock chamber even when the frame-side gassupply port 522 and substrate holder-side gas supply path 525 arecommunicated to each other with air-tightness, which makes it possibleto simplify configuration of the apparatus. In FIG. 32, the substrateholder-side gas supply port 524 is formed in the groove 512 forprotection from a stack ring, but the configuration according to thepresent invention is not limited to this one, and the substrateholder-side gas supply port 524 may be provided in the groove 514, andfurther there is no specific restriction over a form, a position, anumber of this substrate holder-sided gas supply port 524, nor over awidth and a form of the groove section.

With respect to a groove section on a surface of a substrate holder, itis needless to say that attachment of R machined edge section contactinga rear surface of a substrate is effective for preventing damages to arear surface of a substrate. The effect of the lubrication processing toa surface of a substrate holder is the same as that shown in FIG. 29.

FIG. 33 shows configuration of a substrate holder section used in anoptical disk substrate film-formation apparatus according to thefifteenth embodiment of the present invention. The groove section 514 isprovided within a range of a substrate holder covered by a substratewhen the substrate is placed on the substrate holder. Operations andconfiguration in this embodiment are the same as hose shown in FIG. 29,so that detailed description thereof is omitted herein. Although thesubstrate holder-side gas supply port 524 is provided in the groove 512for protection from a stack-ring, the configuration according to thepresent invention is not limited to this one. The substrate holder-sidegas supply port 524 may be provided in the groove 514. Further, there isno specific restriction over the shape, position, and number ofsubstrate holder-sided gas supply ports 524, nor on the width and shapeof the groove section.

With respect to a groove section on a surface of a substrate holder, itis needless to say that attachment of an R machined edge sectioncontacting a rear surface of a substrate is effective for preventingdamages to a rear surface of the substrate. The effect of thelubrication processing to a surface of a substrate holder is the same asthat shown in FIG. 29.

FIG. 34 is a top view showing a general configuration of a general sheettype optical disk substrate film-formation apparatus for forming amulti-layered film according to the sixteenth embodiment. Designated atthe reference numeral 610 is a substrate carry-in/carry-out chamber,designated at 611 to 617 are film-formation chambers, designated at 620is a substrate holder, designated at 621 is an arm, and designated at622 is a rotation shaft.

FIG. 35 shows a cross-sectional structure of a substrate holder based onthe conventional technology in a case where the substrate holder ispositioned in the substrate carry-in/carry-out chamber. Designated atthe reference numeral 631 is a disk substrate, and designated at 632 isa stack ring. Designated at 633 is an inner mask, and designated at 634is an outer mask. Designated at 635 is an electric magnet, anddesignated at 636 is a substrate holder for outward carriage. Designatedat 637 is a substrate holder for inner carriage, and designated at 638is an arm for inward transport. Designated at 639 is a magnet, anddesignated at 640 is a O-ring. Designated at 641 is a frame of anoptical disk substrate film-formation apparatus, and designated at 624is a groove for protection from a stack ring. Designated at 643 is aload lock chamber, and designated at 644 is a lightening section.

FIG. 36 shows a case where the present invention is applied to thesubstrate holder for inward carriage. Designated at the referencenumeral 650 is a substrate holder, and designated at 651 is a groovesection. Designated at 652 is a flow path, and designated at 653 is aventilation port for evacuating inside of the groove. In thisembodiment, a groove 651 having an inner diameter of 28 mm and an outerdiameter of 38 mm is formed around a center of an area where a disksubstrate is placed on a surface of a substrate holder. The depth of thegroove section is 0.5 mm. A portion other than the groove sectionclosely contact the disk substrate.

Using this substrate holder, a dielectric body layer is formed infilm-formation chambers 611, 612, 613, a recording layer in afilm-formation chamber 614, a dielectric body layer in a film-formationchamber 615, and a reflection chamber in film-formation chambers 616 and617 successively. As a material for film-formation, ZnS.SiO₂ is used forthe dielectric body layer, AgInSbTe for the recording layer, and Al forthe reflection layer. The total film thickness is 400 nm. Apolycarbonate substrate with the thickness of 0.6 mm for DVD media isused as the disk substrate. There is no specific restriction overconfiguration of a film-formation chamber, a material for filmformation, a thickness of a film, and a disk substrate.

For comparison, the substrate holder shown in FIG. 38 was used as anexample of the substrate holder based on the conventional technology,and testing for film formation was executed. On a surface of thissubstrate holder, at a position 33 mm away in the radial direction froma center of an area where a disk substrate is placed, three circulargroove sections 651 b each of diameter 15 mm are formed at threepositions in the peripheral direction, and the depth of each of thegroove sections is 0.5 mm. A portion other than the groove sectionclosely contacts the disk substrate.

The multi-layered film is formed on the disk substrate through a seriesof steps including those for carrying a substrate into the substratecarry-in/carry-out chamber, forming a film in the film-formationchambers 1 to 7, and carrying out the substrate from thecarry-in/carry-out chamber. In both of the substrate holders, the groovesection formed on a surface of the substrate holder functions as abent-gas inlet port to a section between a disk substrate and asubstrate holder, so that stable carriage of a substrate is realized andthe effect can be achieved.

However, with the substrate holder based on the conventional technology,although a substrate is closely contacted to a substrate holder, faultsin the mechanical characteristics of the substrate and in media signalcharacteristics are generated, and a cause for this faults is a groovesection formed on a surface of the substrate holder. With the substrateholder according to the present invention, however, the excellentmechanical characteristics of a substrate and excellent signalcharacteristics are obtained. The result is shown in FIG. 39 and FIG.40.

FIG. 39 shows a result of testing executed at a position of T-tilt of 33mm representing the mechanical characteristics of a substrate. Line 660represents a result when the holder according to the present inventionis used, and line 611 represents a result when the holder based on theconventional technology is used. FIG. 40 shows a result at the positionof 33 mm for fluctuation in the reflectance as a representativeparameter for the media signal characteristics. Line 662 represents aresult when the holder according to the present invention is used, andline 663 represents a result when the holder based on the conventionaltechnology is used. The representative characteristics for change in thecharacteristics is shown in this figure, but no remarkable change isobserved in other parameters.

In the substrate holder based on the conventional technology, due toinfluence of the groove section formed on a surface of a substrateholder, the T-tilt is largely disturbed, and also signal fluctuation 664corresponding to the groove section and also indicating fluctuation of areflection factor is observed. Disturbance of the characteristics isalso observed in an area outer from the position of 33 mm in the groovesection. On the contrary, in the substrate holder according to thepresent invention, the T-tilt little changes from the characteristicsbefore execution of film formation, and the excellent mechanicalcharacteristics of a substrate is provided, and no disturbance in thereflectance is observed. A result at the position of 33 mm correspondingto a central position of the groove section is described, but the sameresult is obtained at positions of 28 mm and 33 mm on a rim of thegroove section, and at all of other positions on the inner and outerperipheries.

As described above, in the configuration in which a disk substrate isclosely contacted to a substrate holder, only the configuration ofsubstrate holder according to the present invention insures stablecarriage of a disk substrate and realization of excellent mechanicalcharacteristics of a substrate as well as of excellent media signalcharacteristics, and can satisfy the two requirements simultaneously.When a substrate is closely contacted to a substrate holder, damages maybe given to a rear surface of the substrate holder, but in thisembodiment, by employing the method of providing a taper in an edgesection forming a rim of a groove section, damages caused by contactbetween a rim of the groove section and a disk substrate can be reduced.In this case, the taper is provided by beveling by C 0.3 mm. However,the taper form is not limited to this one.

By executing R machining to the edge section, damages can further bereduced. In this case, the depth of the groove is 1.5 mm, and Rmachining of 1.0 m is executed. The R-machining form is not limited tothis one. In the present invention, when complex plating with PTFEwater-repelling powder is executed to a surface where the substrateholder contacts a disk substrate, damages generated in the area wherethe disk substrate contacts a substrate holder can be reduced. The sameeffect can be obtained also when the substrate holder itself is madefrom PTFE.

FIG. 37 shows another example in which the present invention is appliedto a substrate holder for inward carriage in the optical disk substratefilm-formation apparatus having the configuration as described above. Inthis example a groove section with an inner diameter of 30 mm and anouter diameter of 35 mm and that with an inner diameter of 45 mm and anouter diameter of 50 mm are formed around a center of an areas of thesubstrate holder where a disk substrate is placed. In this case thedepth of the groove section is 0.5 mm. Further, portions other than thegroove section closely contacts the disk substrate. When testing forfilm formation by sputtering is executed using this substrate holder,the same excellent mechanical characteristics and media signalcharacteristics as those described above are obtained at all positionsof the substrate. The result of testing for other parameters is alsoexcellent.

FIG. 41 is a cross-sectional view showing basic configuration of aphase-change recording type of optical disk according to the seventeenthembodiment. As shown in this figure, the optical disk comprises a lowerdielectric body protection layer 702, a phase-change recording layer703, an upper dielectric body protection layer 704, asulfidization-preventing conductive layer 705, an Ag-basedreflection/heat-emission layer 706, a resin adhesion layer 707, and adummy substrate 708 for adhesion successively formed on a substrate 701.The lower and upper dielectric body protection layers are made fromZnS—SiO₂. As clearly shown in this figure, the present invention ischaracterized in that the reflection/heat-emission layer is amulti-layered one, that the sulfidization-preventing conductive layer705 is provided in the side of the dielectric body protection layer, andthat the reflection/heat-emission layer 706 is based on an Ag alloy.Because of this feature, a time required for forming thereflection/heat-emission layer is around one third of that required forforming a single layer based on an Al-based alloy.

The sulfidization-preventing conductive layer in the laminated body ismade from a material having a reaction force with sulfur smaller thanthat of Ag, and fluctuation in reflectance of the material is extremelysmall even when it is contacting ZnS.

The thickness of each of the layer is optimized according to thermalcharacteristics of the layer. In a DVD media using a 635 nm light beam,the thickness of the lower dielectric body protection 702 made from adielectric body having a refraction index of around 2 such as ZnS—SiO₂is between 50 to 250 nm, and preferably between 50 to 80 nm or between160 to 220 nm. In the case of phase-change recording layer 703, amarking is clearly formed for a thermal reason when cooled rapidly, sothat, as far as a chalcogen-based film, the film thickness is in a rangefrom 8 to 30 nm, and preferably in a range from 13 to 22 nm regardlessof whether the material is AgInSbTe or GeSbTe. The upper dielectric bodyprotection layer 704 is required to conduct heat to the heat-emissionlayer, so that the film thickness can not be large. The thickness isbetween 7 to 60 nm, and preferably between 10 to 30 nm. It is betterthat the sulfidization-preventing conductive layer is thicker from aviewpoint of protection of sulfidization of Ag in the upper layer.However, to improve the reliability in repetitively rewriting data byimproving the heat-emission capability, it is better that thesulfidization-preventing conductive layer is thinner than the upperAg-based protection/heat-emission layer. The thickness of thereflection/heat-emission layer in a range from 80 nm or less ispreferable for saturation the reflectance, but the thickness in a rangefrom 100 to 200 nm is preferable for improving the reliability inrepetitively rewriting data by improving the heat-emission capability.

Examples 5 and 6 are described in more detail below.

EXAMPLE 5

Two types of plastic substrate, namely a polycarbonate substrate and apolyolefin substrate each with the thickness of 0.6 mm are prepared.Films are formed on the recording medium (optical disks) shown in Table2 and Table 3 using a magnetron sputter device. Thereflection/heat-emission layer is made from pure Ag. The resultantphase-change recording type of optical disk is maintained in 85% RH for1000 hours under the temperature of 80 degree centigrade, and the biterror rate (BER) is measured. The time point when the BER drops to ahalf of the initial value is regarded as an end of the life.

In Table 2 and Table 3 the film thickness is fixed. Namely, lowerdielectric body protection layer is 150 nm thick, phase-change recordinglayer is 20 nm thick, upper dielectric body protection layer is 20 nmthick, sulfidization-preventing conductive layer is 20 nm thick, andreflection/heat-emission layer is 100 nm thick.

The symbol ◯ in the ‘life’ row indicates a case where the time until abit error rate on the entire surface of a substrate is doubled ascompared to the initial value is 1000 hours or more under the conditionsincluding relative humidity of 85% and temperature of 80 degreecentigrade. The symbol Δ indicates a case where the time is around 800hours, and the symbol X indicates a case where the time is less than 800hours.

Conditions for assessment are 635 nm; Na: 0.60; linear velocity: 3.5m/s; recording density: 0.4 μm/bit.

Film formation speed on the reflection layer: ◯ indicates a case twotimes faster speed than that for Al.

Substrate: PC indicates polycarbonate, and PO indicates polyolefin, and“PC/PC” indicates that the assessment is performed by using these twotypes of substrate.

Recording layer: “AgInSbTe/GeSbTe” indicates that the assessment isperformed for AgInSbTe recording layer and GeSeTe recording layerrespectively.

TABLE 2 Sulfidization- Re- preventing Upper Lower Linear film flection/dielectric dielectric dielectric formation heat- body body Phase-changebody velocity for emission protection protection recording protectionreflection layer layer layer layer layer Substrate Life layer Al nothingZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ X Ag nothing ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO X ◯ Ag AlCu_(0.05) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag AlSi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag Alsi_(0.01)Cu_(0.05) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag AlSc_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO Δ ◯ Ag AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag AlSi_(0.01)Ti_(0.05) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO Δ ◯ Ag Ti ZnS—SiO₂ AgInSbTe/GeSbTeZnS—SiO₂ PC/PO ◯ ◯ Ag Zr ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ AgHf ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag TiN ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯

TABLE 3 Sulfidization- Linear Re- preventing Upper Lower film flection/dielectric dielectric dielectric formation heat- body body Phase-changebody velocity for emission protection protection recording protectionreflection layer layer layer layer layer Substrate Life layer Ag TiSi₂ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag ZrN ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag ZrSi₂ ZnS—SiO₂ AgInSbTe/GeSbTeZnS—SiO₂ PC/PO ◯ ◯ Ag HfN ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ AgHfSi₂ ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag Ta ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag TaN ZnS—SiO₂ AgInSbTe/GeSbTeZnS—SiO₂ PC/PO Δ ◯ Ag TaSi₂ ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯Ag W ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag WN ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ag WSi ZnS—SiO₂ AgInSbTe/GeSbTeZnS—SiO₂ PC/PO ◯ ◯

EXAMPLE 6

Two types of plastic substrate, namely a polycarbonate substrate and apolyolefin substrate each with the thickness of 0.6 mm are prepared. Therecording media (optical disks) shown in Table 4 to Table 6 are formedon each on the substrates using a magnetron sputter device. Thesulfidization-preventing conductive layer is made from AlTi_(0.01). Theresultant phase-change recording type of optical disk is maintained in85% RH for 1000 hours under the temperature of 80 degree centigrade, andthe bit error rate (BER) is measured. The period of time until the BERis doubled as compared to the initial value or more is defined as thelife.

In Table 4 to Table 6, the film thickness is fixed. Namely, lowerdielectric body protection layer is 150 nm thick, phase-change recordinglayer is 20 nm thick, upper dielectric body protection layer is 20 nmthick, sulfidization-preventing conductive layer is 20 nm thick, andreflection/heat-emission layer is 100 nm thick.

The symbol ◯ in ‘life’ row indicates a case where the time until a biterror rate on the entire surface of a substrate is doubled as comparedto the initial value is 1000 hours or more under the conditionsincluding relative humidity of 85% and temperature of 80 degreecentigrade. The symbol Δ indicates a case where the time is around 800hours, and the symbol X indicates a case where the time is less than 800hours.

Conditions for assessment: 635 nm; Na: 0.60; linear velocity: 3.5 m/s;recording density: 0.4 μm/bit.

Film formation speed on the reflection layer: ◯ indicates a case twotimes faster speed than that for Al.

Substrate: PC indicates polycarbonate, and PO indicates polyolefin, and“PC/PC” indicates that the assessment is performed by using these twotypes of substrate.

Recording layer: “AgInSbTe/GeSbTe” indicates that the assessment isperformed for AgInSbTe recording layer and GeSeTe recording layerrespectively.

Reflection/heat-emission layer: For instance, “Ag26%Cu2%Ni” indicatesthat a content of Cu is 26%, Ni 2%, and Ag 72%.

TABLE 4 Sulfidization- Linear Re- preventing Upper Lower film flection/dielectric dielectric dielectric formation heat- body body Phase-changebody velocity for emission protection protection recording protectionreflection layer layer layer layer layer Substrate Life layer Al nothingZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ X Ag nothing ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO X ◯ Ag 26% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Cu 2% Ni Ag 65% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ X W Ag 2% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Pd Ag 1% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO Δ ◯ Cu 1% Ti Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Pd 1% Cu Ag 20% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO Δ ◯ Al Ag 10% AlITi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ In Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ir

TABLE 5 Sulfidization- Re- preventing Upper Lower Linear film flection/dielectric dielectric dielectric formation heat - body body Phase-changebody velocity for emission protection protection recording protectionreflection layer layer layer layer layer Substrate Life layer Ag 5%nothing ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Zr Ag 5% nothingZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ru Ag 5% AlTi_(0.01)ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Cr Ag 5% AlTi_(0.01)ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ V Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ti Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Y Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ce Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Pr Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO Δ ◯ Nd Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Sm Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Eu Ag 5% AlTi_(0.01) ZnS—SiO₂AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Gd

TABLE 6 Sulfidization- Re- preventing Upper Lower Linear film flection/dielectric dielectric dielectric formation heat- body body Phase-changebody velocity for emission protection protection recording protectionreflection layer layer layer layer layer Substrate Life layer Ag 5%AlTi_(0.01) ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Pt Ag 5%AlTi_(0.01) ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO Δ ◯ Rh Ag 5%AlTi_(0.01) ZnS—SiO₂ AgInSbTe/GeSbTe ZnS—SiO₂ PC/PO ◯ ◯ Ta

As shown in Table 4 to Table 6, durability of the disk according to thepresent invention in which the reflection/heat-emission layer is of amulti-layered type, namely the disk in which a sulfidization-preventingconductive layer is used between an Ag-based alloy film and an upperdielectric body protection layer is better than the disk having a singlereflection/heat-emission layer made from Ag. In the description above,the sulfidization-preventing conductive layer is expressed by a generalformula of, for instance, TiN_(x), but the composition is not alwaysidentical to the stoichiometric one. A good result can be obtained witha composition close to the stoichiometric composition which ischemically stable.

Further it is understood from Table 4 to Table 6 that the durability isfurther improved by adding Pd or Rh, Ru, Ni, Cu or the like. Warping ofa substrate is small when an Ag-alloy based reflection/heat-emissionfilm is used, while the warping is large when an Al-basedreflection/heat-emission film is used.

As described above, in the phase-change-recording type of optical diskaccording to the seventeenth embodiment, the dielectric body protectionlayer is made from ZnS-SiO₂, and the reflection/heat-emission layer is alaminated structure of Ag-based alloy/sulfidization-preventingconductive layers. Namely a lower dielectric body protection layer, aphase-change recording layer, an upper dielectric body protection layer,a sulfidization-preventing conductive layer, and an Ag-based alloyreflection/heat-emission layer are laminated on a plastic substrate.

The Ag-alloys described above include, for instance, AgCuNi, AgW, AgPd,AgPdTi, AgPdCu, AgAl, AgIn, AgIr, AgZn, AgRu, AgCr, AgV, AgTi, AgY,AgCe, AgPr, AgNd, AgSm, AgEu, AgGd, AgPt, AgRh, and AgTa. As Ag hasbetter thermal conductivity than Al, a thickness of Ag film may bethinner as compared to that of an Al film to achieve the sameheat-emission effect. Further, the sputter rate of Ag with the samepower is 3 times higher than that of Al. Because of this feature, aheat/emission layer with a small film thickness can be formed at afaster speed, and increase of temperature in the substrate during filmformation can be suppressed. As Ag is sulfidized and changes when itcontacts sulfur, a thin sulfidization-preventing conductive layer isprovided between the Ag-based reflection/heat-emission layer andZnS—SiO₂ protection layer to prevent direct contact between Ag andsulfur, and with this configuration, sulfidization of Ag is sulfidized.

The thickness of the sulfidization-preventing conductive layer shouldpreferably be smaller than that of the reflection/heat-emission layer toimprove the heat-emission capability and reliability in repetitivelyrewriting data. The materials include an Al film of a film made from analloy containing Al; a film made from an alloy containing highmelting-point metal; a film made from an alloy containing Ta; and a filmmade from an alloy containing W. The Al-containing alloy includesAlCu_(x), AlSi_(x)Cu_(y), AlSc_(x), AlTi_(x), or AlSi_(x)T_(y), and inthis case x and y are less than 0.5, preferably less than 0.2, and morepreferably less than 0.1. The film made from an alloy containing highmelting-point metal includes a It film, an Zr film, or an Hf film orTi_(x)N_(y), Ti_(x)Si_(y), Zr_(x)N_(y), Zr_(x)Si_(y), Hf_(x)N_(y), orHf_(x)Si_(y), and in the Ti_(x)N_(y), Zr_(x)N_(y), Hf_(x)N_(y), x+y=1,0.1<x<0.7, preferably 0.3<x<0.6, and more preferably 0.45<x<0.55, andfurther in the Ti_(x)Si_(y), Zr_(x)Si_(y), and Hf_(x)Si_(y), x+y=1,0.1<x<0.7, preferably 0.2<x<0.6, and more preferably 0.33<x<0.53. A filmmade from an alloy containing Ta includes Ta_(x)N_(y) and Ta_(x)Si_(y),and in the Ta_(x)N_(y), x+y=1, 0.1<x<0.7, preferably 0.3<x<0.6, morepreferably 0.45<x<0.55, and in the Ta_(x)Si_(y), x+y=1, 0.1<x<0.7,preferably 0.2<x<0.6, and more preferably 0.33<x<0.53. The film madefrom an alloy containing W comprises W, W_(x)N_(y), or W_(x)Si_(y), andin the W_(x)N_(y), x+y=1, 0.1<x<0.7, preferably 0.3<x<0.6, and morepreferably 0.45<x<0.55, and in the W_(x)Si_(y), x+y=1, 0.1<x<0.7,preferably 0.2<x<0.6, and more preferably 0.33<x<0.53.

As described above, with the present invention, deformation of asubstrate during film formation can be reduced. Because of this feature,even when a thin substrate is used, the substrate can be treated likethose based on the conventional technology, and lowering of through-putin a film-formation step can be prevented. Further, quality of theoptical disk can be improved and yield of production of optical diskscan also be improved. In addition, a substrate can be adsorbed to asubstrate holder with a vacuum chuck, and deformation of the substratecan be prevented. Therefore, quality of the optical disk and yield inproduction of optical disks can be improved. Therefore, with the presentinvention, it is possible to provide an optical disk substratefilm-formation apparatus which does not cause deformation of substrates,nor lower the through-put even when a thinner disk substrate is used.

With the present invention, it is possible to adsorb a substrate to asubstrate holder with vacuum chuck, and even when a substrate with athickness of 0.6 mm, deformation of the substrate can be prevented.Thus, quality of optical disk based on the adhesion system and the yieldin the production of optical disks can be improved.

With the present invention, generation of damages on a light beamincidence surface of an optical disk can be prevented, quality of anoptical disk is improved with yield in production of optical disks alsoimproved.

With the present invention, by adjusting a contact force between acontact holding surface of a substrate holder and a substrate, thesubstrate can easily be removed from the contact holding surface.Therefore, even when a substrate is vacuum-chucked, the substrate can beremoved with a relatively small force, and loss of substrates in theremoval step can be prevented.

With the present invention, a substrate can easily be peeled off from acontact holding surface. Therefore, even when a substrate isvacuum-chucked, the substrate can be removed with a relatively smallforce, and loss of substrates in the removal step can be prevented.

With the present invention, a substrate holder and a substrate can beadsorbed to each other by generating a pressure difference between afilm formation chamber and a substrate carriage chamber. Because of thisfeature, configuration of the optical disk substrate film-formationapparatus according to the present invention can be simplified, and itis possible to automatically cancel adsorption of an optical disk and toprevent loss of substrates in the removal step.

With the present invention, by making the substrate holding surface of asubstrate holder rough, warping of a substrate in the radial andperipheral directions thereof can be suppressed. Further, adhesion of asubstrate to a substrate holder is eliminated. Therefore, easiness inpeeling off a substrate from a substrate holder is improved.

With the present invention, by setting the surface roughness Rmax of aportion of the substrate holding surface between 10 μm to 500 μm, theeffect described above is remarkably improved.

With the present invention, warping of a substrate can be suppressed,and in addition easiness in taking out a substrate from a substrateholder after film formation is finished is further improved. Further,the advantage that damages are hardly generated on a rear surface of asubstrate is obtained.

With the present invention, by locating a porous member between aportion which a surface of a plastic plane substrate on which a film isnot formed contacts and a portion off from the former portion to linkthe two sections, it is possible to maintain the thermal deformationprevention effect and the air-tight adhesion prevention effect in aplastic plane substrate can be maintained without reducing themechanical strength of a substrate holder.

With the present invention, by locating a porous member in an areacontacting an area not contacted by a plane substrate, and also byproviding a through-hole penetrating a substrate holder on a rearsurface of the porous member, scattering materials generated during filmformation are not deposited thereon, so that the necessity of replacingthe porous member is eliminated, and it is possible to maintain theeffects of preventing thermal deformation and the air-tight adhesion ofa substrate.

With the present invention, the porous member is made from a materialwith high thermal conductivity, so that discontinuity in thermaldistribution on a surface of a substrate holder is not generated, and itis possible to maintain the effects for preventing thermal deformationand air tight adhesion prevention of a substrate in the most stableconditions.

With the present invention, the porous member is made from a polymericmaterial or a material with the surface covered with a polymericmaterial, so that it is possible to maintain the effects of preventingthermal deformation and air tight adhesion of a substrate without givingdamages to a surface of a substrate.

With the present invention, the porous member is made from an elasticmaterial, so that it is possible to maintain the effects of preventingthermal deformation and air tight adhesion prevention of a planesubstrate without giving damages to a surface of the substrate.

With the present invention, deformation of a substrate during firmformation can be prevented, and in addition the entire rear surface ofthe substrate does not contact a substrate holder, so that it ispossible to prevent the operation for taking out a substrate by means ofvacuum adsorption from becoming unstable. Further, it is possible toprovide an optical disk which causes deformation of a substrate littleand can carry substrate under stable conditions.

With the present invention, it is possible to provide a thickness of anoptical disk preventing deformation of a substrate and enabling a stableoperation for taking out the substrate.

With the present invention, by giving a tapered shape to an edge of asupport holding section of a substrate holder, it is possible to preventa concentrated mechanical load to a substrate. Further, it is possibleto prevent local damages in the substrate and damages to a surface ofthe substrate.

With the present invention, it is possible to give an optical taperangle to a tapered form given to an edge of a support holding section.

With the present invention, it is possible to prevent damages to asurface of a substrate by forming an edge of a support holding sectionwith a material with hardness higher than that of a substrate.

With the present invention, it is possible to give optimal dimensions tothe material with low hardness used in an edge section of a substrateholder.

With the present invention, a specific material with lower hardness usedin an edge section of a substrate holder is given, and it is possible toimprove the effect of preventing damages to a surface of a substrate byusing the material.

With the present invention, it is possible to introduce gas from a gassupply section provided on a surface of the substrate holder in alimited portion between a substrate placement surface of a substrateholder and a substrate on which a film is to be formed, and in a closedspace portion formed in the range by contact between the substrate andsubstrate holder. Because of this feature, it is possible to efficientlyexecute operations for taking out and carrying a substrate with a filmhaving been formed thereon at a high speed. Even when the gas inlet portof a frame of an optical disk substrate film-formation apparatus and thegas supply port of the substrate holder are air-tightly communicated toeach other, it is possible to evacuate inside of a flow path from a gasinlet path of the frame of the optical disk substrate film-formationapparatus to the gas supply section of the substrate holder to a vacuumstate. Further even when a substrate is closely contacted to a substrateholder, there is provided the extremely excellent advantage that damagesto a rear surface of a substrate can be prevented.

With the present invention, it is possible to realize a substrate holderbased on a structure in which at least a portion of a film-formed areais closely contacted to a substrate holder which can obtain theexcellent mechanical characteristics and media signal performance of asubstrate, even though a groove is prevent on a surface of the substrateholder, when film formation by sputtering is executed. Namely, it ispossible to provide an optical data recording medium insuring theexcellent mechanical characteristics and media signal performance evenwhen high speed film formation, formation of a large thickness, filmformation on a thin disk are performed, or when two or more layers areformed repetitively on the same substrate. Further by eliminatingtroubles in carrying substrates when film formation is executedcontinuously, and also by substantially improving serviceability of theoptical disk substrate film-formation apparatus, there is provided theextremely excellent advantage that production efficiency issubstantially improved and the production cost is reduced.

With the present invention, by providing a rim of the groove section ata concentric position against a center of the optical disk, it ispossible to substantially reduce influence of a groove section formed ona surface of the substrate holder over the mechanical characteristicsand media signal performance of a substrate.

With the present invention, by providing a taper in an edge sectionforming a rim of the groove section or executing R machining thereto,damages of a rim section of a groove formed in the substrate holdercaused by contact with the disk substrate can be reduced.

With the present invention, by executing a complex plating withwater-repelling powder of carbon fluoride (Cf)n or fluororesin (PTFE,PFE, EFP) or executing the processing for water repulsion with achlorosilane-based chemical adsorbent having a fluoroalkyl base, damagescaused by contact between a disk substrate and a substrate holder cansubstantially be reduced.

With the present invention, by forming a surface of a substrate holderwhere it contacts a disk substrate with a lubricating material such asPTFE or polyacetal, damages caused by close contact between a disksubstrate and a substrate holder can substantially be reduced.

With the present invention, by forming a flow path communicating to thegroove section, when a disk substrate is carried out from an opticaldisk substrate film-formation apparatus, it is possible to introduce aventilation gas from this non-contact space, whereby generation ofvacuum chucking generated when the disk substrate is closely contactedto the substrate holder can be prevented, and stable carriage ofsubstrates can be carried out.

With the present invention, deformation of a substrate during filmformation can be reduced. Because of this feature, even when a thinnersubstrate is used, the substrate can be treated like that based on theconventional technology, and in addition lowering of through-put in thefilm-formation step can be prevented. Further, quality of optical diskcan be improved with yield of optical disk production also improved. Inaddition, even when a thinner substrate is used, deformation of thesubstrate can be prevented. Because of the feature, quality of opticaldisks can be improved, and also yield in production of optical disks canbe improved. For the reasons described above, with the presentinvention, even when a thinner optical disk is used, it is possible toprovide an optical disk substrate film-formation apparatus which doesnot deform a disk substrate, nor lowers the through-put.

With the present invention, a substrate can be adsorbed to a substrateholder by means of vacuum chucking, and even when a substrate with thethickness of 0.6 mm, deformation of the substrate can be prevented.Because of this feature, quality of optical disks based on the adhesionsystem can be improved, and also yield of production of optical diskscan be improved.

With the present invention, a substrate holder and a substrate areadsorbed to each other during film formation without the need ofproviding a dedicated mechanism for adsorbing the substrate holder and asubstrate. Because of this feature, it is possible to simplifyconfiguration of the optical disk substrate film-formation apparatusaccording to the present invention, and to prevent a substrate frombeing broken when adsorption of the optical disk is automaticallyreleased and the substrate is removed.

With the present invention, a substrate holder and a substrate can beadsorbed to each other during film formation without the need ofproviding a dedicated mechanism for adsorbing the substrate to thesubstrate holder. Because of this feature, configuration of the opticaldisk substrate film-formation apparatus according to the presentinvention is simplified, and it is possible to prevent a substratehaving a thickness of 0.6 mm or less when adsorption of the optical disksubstrate is automatically released and the substrate is removed.

With the present invention, deformation of a substrate can be reduced.Because of this feature, even when a thinner substrate is used, filmformation can be performed like on the conventional type of substrate,and in addition lowering of through-put in the film-formation step canbe prevented. Further quality of optical disk substrate can be improved,and also yield in production of optical disks can be improved. Further,a substrate can be adsorbed to a substrate holder by means of vacuumchuck, and even when a thinner substrate is used, deformation of thesubstrate can be prevented. Therefore, quality of optical disks can beimproved, and also yield in production of optical disks can further beimproved. For the reasons described above, with the present invention,it is possible to provide an optical disk substrate film-formationmethod in which, even when a thinner optical disk is used, the opticaldisk substrate is not deformed and the through-put is not lowered.

With the present invention, damages to an light beam incidence surfaceof an optical disk which is a rear surface during film formation can beprevented, and quality of the optical disk can be improved with theyield in production of optical disks further improved.

With the present invention, it is possible to form a protection filmwithout loading heat to a substrate, and to further reduce deformationof a substrate due to heat.

With the present invention, even when such as device as a coater is notavailable, it is possible to form a protection film, which allowsvarious methods for forming a protection method.

With the present invention, conditions for film formation are wellknown, and a film made from a material suited to the protection film canbe selected. Because of this feature, it is possible to form aprotection film suited to protection of a rear surface of the substrate.

With the present invention, substrate, which are not warping, can beproduced with high yield.

With the present invention, a substrate holder can easily bemanufactured with low cost. Preferably triazine is used for processing asurface of a substrate holding surface, and the surface lubricationeffect can be achieved with relatively low cost.

With the present invention, it is possible to provide an optical diskwhich enables improvement in the production efficiency and reduction ofproduction cost.

With the present invention, a phase-change type of optical disk in whichan Ag-based alloy film is used for the reflection/heat-emission layer,and a sulfidization-preventing conductive layer is provided between theupper dielectric body protection layer made from a mixture of zincsulfide and silicon oxide and the reflection/heat-emission layer isprovided. With this phase-change recording type of optical disk, filmformation by sputtering can be executed on the disk at a higher speed ascompared to a case where Al is used for the reflection/heat-emissionlayer. In addition the warping amount is small because the temperaturedoes not rise so much. Further degradation of Ag can be suppressedbecause of existence of the sulfidization-preventing conductive layer.

Although the invention has been described with respect to a specificembodiment for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art which fairly fall within the basic teaching hereinset forth.

1. An optical disk substrate film-formation apparatus which manufactures an optical disk by forming a thin film on the surface of a substrate, said apparatus comprising: a substrate holder which fixes said substrate during the formation of said film, wherein said substrate holder includes, a contact holding surface contacting at least a portion of a rear surface of a film-formed area of said substrate on which said film is formed, a vacuum chuck section for adsorbing and fixing said contact holding surface to said substrate, and a removal claw having an inclined section configured to go into a section between a rear surface of the substrate and a top surface of the substrate holder to mechanically peel off the adsorbed substrate from the substrate holder.
 2. The optical disk substrate film-formation apparatus according to claim 1, wherein said contact holding surface is made from a material with a hardness lower than said substrate.
 3. The optical disk substrate film-formation apparatus according to claim 1, wherein said substrate bolder has a vacuum chuck section for adsorbing and fixing said contact holding surface to said substrate, and said contact holding surface has a groove section.
 4. The optical disk substrate film-formation apparatus according to claim 1, wherein said substrate holder has a vacuum chuck section for adsorbing and fixing said contact holding surface to said substrate; and a removal claw for removing the adsorbed substrate.
 5. The optical disk substrate film-formation apparatus according to claim 1, wherein said substrate holder is located between a film-formation chamber in which film formation for a substrate is performed and a substrate carriage chamber in which a pressure is maintained at a lower level than that in said film-formation chamber, and said contact holding surface has a through-hole communicated to said substrate carriage chamber and to said film-formation chamber.
 6. An optical disk substrate film-formation apparatus which manufactures an optical disk by forming a thin film on the surface of a substrate, said apparatus comprising: a substrate holder which fixes said substrate during the formation of said film, wherein said substrate has a thickness of 0.6 mm or less, and wherein said substrate holder includes, a contact holding surface contacting at least a portion of a rear surface of a film-formed area of said substrate on which said film is formed, a vacuum chuck section for adsorbing and fixing said contact holding surface to said substrate, and a removal claw having an inclined section configured to go into a section between a rear surface of the substrate and a top surface of the substrate holder to mechanically peel off the adsorbed substrate from the substrate holder.
 7. The optical disk substrate film-formation apparatus according to claim 6, wherein said contact holding surface is made from a material with a hardness lower than said substrate.
 8. The optical disk substrate film-formation apparatus according to claim 6, wherein said substrate holder has a vacuum chuck section for adsorbing and fixing said contact holding surface to said substrate, and said contact holding surface has a groove section.
 9. The optical disk substrate film-formation apparatus according to claim 6, wherein said substrate holder has a vacuum chuck section for adsorbing and fixing said contact holding surface to said substrate; and a removal claw for removing the adsorbed substrate.
 10. The optical disk substrate film-formation apparatus according to claim 6, wherein said substrate holder is located between a film-formation chamber in which film formation for a substrate is performed and a substrate carriage chamber in which a pressure is maintained at a lower level than that in said film-formation chamber, and said contact holding surface has a through-hole communicated to said substrate carriage chamber and to said film-formation chamber.
 11. An optical disk substrate film-formation apparatus comprising: a substrate holder which holds a substrate at its rear surface so that sputter film formation can be carried out on the front surface of said substrate, wherein said substrate holder includes, a substrate holding surface which comes in contact with said rear surface of said substrate, a vacuum chuck section for adsorbing and fixing said contact holding surface to said substrate, and a removal claw having an inclined section configured to go into a section between a rear surface of the substrate and a top surface of the substrate holder to mechanically peel off the adsorbed substrate from the substrate holder.
 12. The optical disk substrate film-formation apparatus according to claim 11, wherein the surface roughness Rmax (maximum height) of said substrate holding surface is 10 μm or more and less than 500 μm.
 13. The optical disk substrate film-formation apparatus according to claim 12, wherein lubrication is provided at at least a portion of said substrate holding surface, and the surface roughness Rmax at the portion where the lubrication is provided is 10 μm or more and 500 μm or less.
 14. The optical disk substrate film-formation apparatus according to claim 12, wherein at least a portion of said substrate holding surface is made from a self-lubricating plastic material, and the surface roughness Rmax of the portion made from the self-lubricating plastic material is 10 μm or more and 500 μm or less.
 15. An optical disk substrate film-formation apparatus comprising: a substrate holder which holds thereon a substrate as an object for film formation, said substrate holder having, a groove section which extends from a portion where said substrate holder contacts said substrate when said substrate holder is holding said substrate to a portion where said substrate holder does not contact said substrate when said substrate holder is holding said substrate, and a porous member which can allow air to pass through provided within said groove section in which the surface of the porous member is at a same level as the surface of substrate holder.
 16. The optical disk substrate film-formation apparatus according to claim 15, wherein said porous member is made from a thermal conductivity material.
 17. The optical disk substrate film-formation apparatus according to claim 15, wherein said porous member is made from a polymeric material or a material with a polymeric material laminated on the surface.
 18. The optical disk substrate film-formation apparatus according to claim 15, wherein said porous member is made from an elastic material.
 19. An optical disk substrate film-formation apparatus comprising: a substrate holder which holds thereon a substrate as an object for film formation, said substrate holder having, a groove section in a portion where said substrate holder contacts said substrate when said substrate holder is holding said substrate, a porous member which can allow air to pass through provided within said groove section in which the surface of the porous member is at a same level as the surface of substrate holder, and a through-hole which connects said groove section to the portion where said substrate holder does not contact said substrate when said substrate holder is holding said substrate, wherein said substrate holder is located between a film-formation chamber in which film formation for a substrate is performed and a substrate carriage chamber in which a pressure is maintained at a lower level than that in said film-formation chamber, and wherein said through-hole directly communicates with air within the substrate carriage chamber.
 20. The optical disk substrate film-formation apparatus according to claim 19, wherein said porous member is made from a thermal conductivity material.
 21. The optical disk substrate film-formation apparatus according to claim 19, wherein said porous member is made from a polymeric material or a material with a polymeric material laminated on the surface.
 22. The optical disk substrate film-formation apparatus according to claim 19, wherein said porous member is made from an elastic material.
 23. An optical disk substrate film-formation apparatus comprising: a substrate holder which holds thereon an optical disk substrate as an object for film formation; an inner mask which masks a specified area on an inner side of said optical disk; and an outer mask which masks a specified area on an outer side of said optical disk; wherein said inner mask and said outer mask being used for forming a thin-film on a surface of said optical disk substrate, said substrate holder having, a substrate holding section which contacts said optical disk substrate on the rear surface of said optical disk substrate but in a portion where the thin-film has been formed on the front surface, wherein said substrate holding section contacts said optical disk substrate in the portion extending between a line which is 2 to 10 mm on the outer side of an edge of said inner mask and a line which is 0.5 to 5 mm on the inner side of an inner edge of said outer mask.
 24. The optical disk substrate film-formation apparatus according to claim 23, the thickness of said optical disk substrate is between 0.3 to 0.8 mm.
 25. The optical disk substrate film-formation apparatus according to claim 23, wherein an edge of said substrate holding section is tapered.
 26. The optical disk substrate film-formation apparatus according to claim 25, wherein a taper angle is the angle between the tapered surface obtained by tapering and the surface of said substrate holding section where said optical disk substrate contacts said surface holding section, and the taper angle is between 1.0 to 2.0 degree.
 27. The optical disk substrate film-formation apparatus according to claim 23, wherein an edge of said substrate holding section is made from a material having a hardness lower than the hardness of said optical disk substrate.
 28. The optical disk substrate film-formation apparatus according to claim 27, wherein the width of the portion made from the material having a lower hardness, in the radial direction of said optical disk, is between 0.1 to 0.5 mm.
 29. The optical disk substrate film-formation apparatus according to claim 27, wherein said material of the edge of the substrate holding section is silicon rubber.
 30. An optical disk substrate film-formation apparatus used for sputter film formation in which a laminated film is formed by combining any one or two or more of a reflection layer, a recording layer, a protection layer, or a dielectric body layer on a disk substrate in an optical disk manufacture step comprising: a gas supply section for introduction of gas in a substrate holder side in a limited portion between a substrate setting surface of a substrate holder and a film-formed substrate, and at least a closed space section in the area formed in the substrate holder side because of contact between the substrate and substrate holder, wherein gas is supplied from the gas supply section during a period from a time point when sputter film formation is finished until a time point when a substrate is carried out, and wherein the gas supplied from said gas supply section is also used as vent-gas for a load lock chamber between atmosphere for inserting a substrate into or carrying out from the optical disk substrate film-formation apparatus and vacuum.
 31. The optical disk substrate film-formation apparatus according to claim 30, wherein a gas inlet port for introducing gas from outside of the optical disk substrate film-formation apparatus is provided in an internal wall of a frame of the optical disk substrate film-formation apparatus forming a closed space of the load lock chamber, a gas supply port communicating to gas supply section is provided in said substrate holder, and said gas inlet port of the frame of the optical disk substrate film-formation apparatus and said gas supply port of said substrate holder are communicated to each other only when said substrate holder moves to a specified position of the load lock chamber.
 32. The optical disk substrate film-formation apparatus according to claim 31, wherein said gas inlet port of a frame of the optical disk substrate film-formation apparatus and said gas supply port of said substrate holder are connected to each other via an O-ring.
 33. The optical disk substrate film-formation apparatus according to claim 30, wherein the apparatus has a tapered structure on which a joint section of a gas inlet port of the frame of said optical disk substrate film-formation apparatus and that of a gas supply port of said substrate holder are positioned one above another.
 34. The optical disk substrate film-formation apparatus according to claim 31, further comprising: a bypass valve which communicates with the gas inlet port of the frame of said optical disk substrate film-formation apparatus to a load lock chamber, said bypass valve being provided in a gas inlet path formed by joining said gas inlet port of the frame of the optical disk substrate film-formation apparatus to said gas supply port of said substrate holder, wherein said bypass valve is opened only when the load lock chamber is evacuated to a vacuum state.
 35. The optical disk substrate film-formation apparatus according to claim 33, further comprising: a bypass valve which communicates with the gas inlet port of the frame of said optical disk substrate film-formation apparatus to a load lock chamber, said bypass valve being provided in a gas inlet path formed by joining said gas inlet port of the frame of the optical disk substrate film-formation apparatus to said gas supply port of said substrate holder, wherein said bypass valve is opened only when the load lock chamber is evacuated to a vacuum state.
 36. The optical disk substrate film-formation apparatus according to claim 31 further comprising: an evacuation path which can independently be evacuated to a vacuum state is provided in a gas inlet path of the frame of said optical disk substrate film-formation apparatus formed by joining said gas inlet port of the optical disk substrate film-formation apparatus to said gas supply port of said substrate holder, wherein evacuation to a vacuum state from the evacuation path is performed only when the load lock chamber is to be evacuated to a vacuum state.
 37. The optical disk substrate film-formation apparatus according to claim 33 further comprising: an evacuation path which can independently be evacuated to a vacuum state is provided in a gas inlet path of the frame of said optical disk substrate film-formation apparatus formed by joining said gas inlet port of the optical disk substrate film-formation apparatus to said gas supply port of said substrate holder, wherein evacuation to a vacuum state from the evacuation path is performed only when the load lock chamber is to be evacuated to a vacuum state.
 38. The optical disk substrate film-formation apparatus according to claim 30, wherein the edge of the substrate holder forming a border between a contact section in which a rear surface of the substrate and the substrate holder contact to each other when the substrate is loaded on said substrate holder and a non-contact section, or at least a hole edge section of said gas supply section is machined.
 39. The optical disk substrate film-formation apparatus according to claim 30, wherein a surface of said substrate holder is lubricated via a lubrication process.
 40. The optical disk substrate film-formation apparatus according to claim 39, wherein the lubricating process includes one of a water-repelling processing including complex plating with water-repelling powder using carbon fluoride (Cf)n or fluororesin (PTFE, PFE, FEP), or processing with a chlorosilane-based chemical adsorbent having a fluoroalkyl base.
 41. A substrate holder which holds thereon a substrate as an object for film formation in an optical disk substrate film-formation apparatus, said substrate holder comprising: a groove section which extends from a portion where said substrate holder contacts said substrate when said substrate holder is holding said substrate to a portion where said substrate holder does not contact said substrate when said substrate holder is holding said substrate; and a porous member which can allow air to pass through provided within said groove section in which the surface of the porous member is at a same level as the surface of the substrate holder. 